Imagecrafter

{T}: Choose a creature type other than Wall. Target creature becomes that type until end of turn.

Mistform Mutant

{1}{U}: Choose a creature type other than Wall. Target creature becomes that type until end of turn.

Artificial Evolution

Change the text of target spell or permanent by replacing all instances of one creature type with another. The new creature type can't be Wall. (This effect lasts indefinitely.)

Standardize

Choose a creature type other than Wall. Each creature becomes that type until end of turn.

Gor Muldrak, Amphinologist

You and permanents you control have protection from Salamanders.
At the beginning of your end step, each player who controls the fewest creatures creates a 4/3 blue Salamander Warrior creature token.

Amoeboid Changeling

Changeling (This card is every creature type.)
{T}: Target creature gains all creature types until end of turn.
{T}: Target creature loses all creature types until end of turn.

Unnatural Selection

{1}: Choose a creature type other than Wall. Target creature becomes that type until end of turn.