Redit and build help

some reason i cant post on redit not a trusted user? which clads supports best fir one creatute builds

There is the Discord if you want help theorycrafting builds. Thylacine Studios
Now, if you just started playing, dont do a one creature build until a bit into the game were you will be able to unlock all the other classes besides the starter ones, the one that interest you being Druid, but you can and should unlock all of them.
Druid has many perks that benefit having 1 creature, but it also has a perk that allows you to have 2 extra creatures without counting against its bonuses, thou you still can run a one creature if you want.

There are other classes like Animator or Grovetender who focus on a special creature but they are made to work on teams. There is also the pariah class but that class limits your creatures as a challenge not for bonuses

Technically speaking thou, i would say most classes can work with one creature but have no inherent bonuses to it, with the exception of Animator, because it has synergies with creatures depending on their position in the team; Atrologer, who is literally about making a self suficient organized team; Tribalist because, well, duh, its the class for tribal bonuses; Purgatorian because if your only creature is dead you have lost; Fanatic because its tribalist deluxe; and, dont take my word to seriously on this, probably Spellweaver, i dont know why, just a guess with that of needing a spell of each class, which without very specific perks or traits you aint getting it done early or even middle game mate.