RisenDeep

What's the reason you put Master of the Pearl Trdent, an aggro card, into a control deck?
There are so many Merfolk cards you could use, that have a control aspect, that I don't see why you should play Augur of Bolas or the Master. Talrand may be good as a 1 drop but there are also even sronger cards in the game.

There are a lot of cards that benefit from interaction with an opponent, for example Brineborn Cutthroat benefits from spells you play during an opponents turn to get stronger permanently or Cosi's Trickster (shuffling an opponents library) or even Wake Thrasher (the more lands you tap for mana, the stronger it gets).

Other cards can control opponents like Dakra Mystic, which can cause every player to either draw or waste the top card of their decks. Grimoire Thief lets you exile the top cards every time it gets tapped and you can also sacrifice it to counter spells exiled if needed. Merfolk Windrobber also shrinks the library and you can sacrifice it to draw a card, for example before it gets bolted. Riptide Pilferer targets cards in your opponents hand instead.

Cards that benefit from massive counter spam are first and foremost Lullmage Mentor, which generates tokens and also free counters while playing, while Sigil Tracer lets ya copy your and/or opponent's spells easily. Tazeem Roilmage is not that big of an impact but I added it because you can get your spells back if you want (it's not as strong as Snapcaster Mage but ok, depending on your desired power level). Umara Wizard dosen't interact with your spells on the same level as Lullmage Mentor but it could be a free drop for your deck as it is a dual sided card which can also be playeds as mana source.

Some cards that have control aspect in case of keeping the board clean are for example Harbinger of the Tides, Razorfin Abolisher and Surgespanner, which all have the ability to return permanents to their owner's hand. Merfolk Trickster is a different kind of usecase as it doesn't return cards but removes creature's abilities for a turn.

What's a good control deck without any stealing, fortunately, there are at least 3 cards I can suggest to steal opponent's stuff. Rootwater Matriarch permanently get's control of creatures that are enchanted, regardless of if they remain enchanted. Thada Adel, Aquisitor and Thieving Skydiver both can grab opponent's artifacts and Skydiver also has the ability to equip them, so it plays really well with Colossus Hammer to get a 12/11 creature for {1}{U} + {1} for it's Kicker cost.

Last but not least Kopala, Warden of Waves as your counter-buddy to protect the one or other Merfolk or even a Mutavault from being targeted.

You see there is so much more potential in Merfolk than Talrand, you just have to utilize them

Intruder Alarm is ok, but I guess you 'll have better chances with Freed from the Real as you can also play against Torpor Orb and co.

A card I suggest from time to time is Patron Wizard. The card is useful as most of your creatures are Wizards as well so you can tap them for a free counter at every time.

Also another card from new Zendikar set, Thieving Skydiver. You can grab your opponents Artifacts or just play it for 2 as a 2/1 body with Flying

Have you playtested it?
I don't guess it will work well, anyways here is a beginning of a list I made quickly, use it or again try to run your own but it is clean and has space left for creativity:

//Artifact (10)
2 Conjurer's Bauble
4 Dragon Arch
4 Prophetic Prism

//Basic Snow Land (15)
15 Snow-Covered Island

//Creature (7)
1 Bladewing the Risen
1 Darigaaz, the Igniter
1 Dragonlord Dromoka
1 Dragonlord Kolaghan
1 Dromar, the Banisher
1 Intet, the Dreamer
1 The Ur-Dragon

//Instant (9)
3 Metallic Rebuke
3 Thirst for Knowledge
3 Whir of Invention

//Snow Artifact (4)
4 Arcum's Astrolabe

//Land (1)
1 Academy Ruins

I liked cheating in Darksteel Colossus back in the good old days of Legacy with Gamekeeper and Cabal Therapie so this deck is made right for me :D

+1 just for the name

Depends what you try to achieve, running Kaalia as your main win-con (which I don't suggest) or Dragon Arch to cheat them into play or even playing them from your hand. Anyways, I suggest to cut down everything that is just a fatty to 1 or two at max and your main threats to 3 or 4, so:

- Either a B/W base with R splash, R/W base with B splash or R/B with B splash to be able to play Kaalia and remove some threats from your opponent. There are plenty of options like Path to Exile, Dreadbore, Fatal Push you can utilize to achieve that and even Thoughtseize to strip off their hand and finally play Kaalia, or you go with good old Gamekeeper, Dark Ritual and Cabal Therapy combo

- Or you set a primary blue mana base up for fetching your deck for Dragon Arch and getting it out as soon as possible while disrupting your opponents game as well. A slight control shell could work here as well as an Artifact one with Metallic Rebuke and for example Grand Architect and some cheap artifacts like Pentad Prism, Prophetic Prism, Powerstone Shard to provide the energy used for Dragon Arch fast, then fetch your deck for your fatties and pull them onto the battlefield one after another, for example by also utilizing Voltaic Key

- Or you keep playing them from your hand or with a spell like Dragonstorm, then you barely have another chance than playing a Red, maybe black splashed mana base for Dragonlord's Servant, Dragonspeaker Shaman and Nightscape Familiar which all reduce the cost of your Dragon- and/or red spells so you are able to cast some of your threats early. In this case you should really remove unusual color combinations that don't include red and/or black and set more for Dragons of those colors with just one more splash of a color of your choice. Green can be also nice for some mana ramp and has Darigaaz, the Igniter and Hellkite Overlord as options. Other cool B/R Dragons are Swift Warkite and Bladewing the Risen which both also help you return dead threats from your graveyard

Now its up to you

If you would consider playing "only" multicolored Dragons then Dragon Arch is your best friend. Expensive to get out onto the playground but very useful. If you also agree on playing just legendary Dragon spells, Captain Sisay is also very useful forgetting the Dragons in reach you want to play and finally Intet, the Dreamer can as well bring your scaled troups into play

From the MTG Wiki
"Jumpstart is a supplemental Magic booster set with mostly reprints and some new cards. It was intended to be released on June 26, 2020, but this was pushed back to July 17.[2][3][4][5][6] The set is closely tied to Core Set 2021 but is a stand-alone product. It melds an easy way of deckbuilding with the “shuffle up and play” speed of constructed. In this, it is similar to the Smash Up game of the Alderac Entertainment Group and Richard Garfield's KeyForge."

KeyForge came out 2018 but SmashUp already existed in 2012

- https://en.wikipedia.org/wiki/KeyForge
- https://boardgamegeek.com/boardgame/122522/smash

Jumpstart is not meant as a regular playset rather than a total new way of playing unique Magic games and so is not Standard, Pioneer or even Modern legal as well. With Jumpstart, you are grabbing two of a set of archetype decks, schuffle them together and play with what you get, this is how I understood the purpose of it

Because of the power level of cards reprinted/ created in Modern Horizons. Opening the doors for another Force of Will in formats like Pioneer or even Standard is the last Wizards wants. Pioneer is made to limit the card pool for those players willing to play more advanced formats than standard but don't own the card base to do so as Modern was introduced to start from 8ED back in 2003 and so the card pool is not much newer than in Legacy or Vintage

You could exchange Merrow Harbinger for Forerunner of the Heralds, it's ability is the same except that it gets additional counters whenever a Merfolk enters the game instead of Islandwalk and has a greater body than Harbinger. Islandwalk might not be that important if you play Lords anyways.

Also Deeproot Elite might not be that useful at all, either go for counters or boost your guys but both seems a little odd to me. Insteadd push Mistbinder from SB to main to get a more stable gameplay.

You could also think about replacing some of your lands to make room for Lumbering Falls, it comes into play tapped thats a con but gets a man-land with hexproof which is a pro for th final hit

Stream of Thought is Modern Horizons and not Pioneer legal

If you argue like this, my decks could cost 5000$ an I could say "yeah, this is budget compared to Vintage".
So no it isn't, this is stupid! If you make it budget then it should be budget and should not contain cards that you pay 30$ for a playset. The challange to make a deck budget is that you need to find cards that replace the more expensive ones and result in a comparable matchup. It is not possible all the time but hey, that's a challange to solve and go like if you don't own anything of it. If you own most of the cards and give a statement like "yeah but I own most of it and just need to buy these 10$ playset so it is budget", it is worth nothing too, you instead should act like you fresh started and don't own anything to really say it is budget!

This is my opinion to this topic

Maybe add Joung Pyromancer to benefit from all the spells

This doesn't look really budget-ish

Thank you!

As the comments below your deck point out
"Normally I hate looking at commander decks because they are so damn full of cards"

So I'm not playing highlander/EDH at all but gave a +1 for it since it looked really promising.
I own a playset of Ashling since Lorwyn because I'm honestly a Merfolk guy but have some cards I really like and Ashling is one of them so I thought of how could she benefit from the Ozolith, which is a card I really like too.

There could for sure be the one or other improvement on this but feels fun to play

Already thought about making either a mono black or GB diner themed deck with cards like Bake into a Pie and Trail of Crumbs also based on the cat and oven. Like a feast that will be hold in a castle. This sounds ... tasty!

Yorion in this case can exile what is a plus to finish the game when you have the chance to bake the cat 8 instead of 4 times a turn which is at least 9 life you can drain in a single turn for 1 cat and 4 Ofens or even more if you have more cats and/or also have Bastion or Celebrant on the table

... which you need to play and get onto the next turn to attack and hope opponent doesn't has any creature hate in his deck. Sorry but Quiltspike is a very bad choice to be the primary win-con. Same for everything that can potentially run into a Wrath of God or something similar.

This is the reason why Elfball played Fireball or something like that to finish immediately