budget merfolk

Wont play it like that but let me explain:

Deeproot Elite and Merfolk Mistbinder are good options even while the one dosent benefit from the other. This means Mistbinder "just gives" +1/+1 while Elite adds counters but ok, a solid foundation. I would also add Metallic Mimic if you can get your hands on a playset

Forerunner of the Heralds seems way to expensive for what he is doing. Merfolk is not as powered in standard as it is in modern so you should be fast as hell to beat any other deck in the format.

Kopala, Warden of Waves is a good choice too for end game protection, you should test if a 2 drop is enougth or should be 3 ones. An alternative could be Swift Warden.

Jade Bearer should be set as 4 drop too because it powers your guys additionally and itself provides an additional body. Works well in combination with Deeproot Elite.

Jungleborn Pioneer could help getting more bodies to beat down your opponent and it also profits from Deeproot Elite, both Pioneer and the token.

Merfolk Branchwalker should be double paired with Silvergill Adept, while Merfolk Branchwalker explores Silvergill Adept will draw cards. Both has advantages on its own and both should be played.

Seafloor Oracle can help fetching whatever you need in late game.

Dont play Admiral's Order, this spells alternate casting cost may be not triggered as often as you would like to and you cant use it in early turns when not attacking. Instead focus on Blossoming Defense, a full playset should work here.

Deeproot Waters dont give that benefit you need. You need to cast it turn 3 and play an additional guy turn 4, to get a 1/1 token. You can spend your mana to other spells instead so cut that