The Magma, Steam, Ice, and Dust mephits are available for free as part of the Basic Rules. The Smoke Mephit is a part of the Monster Manual. You would need to either:
1) Purchase the Smoke Mephit individually from the Monster Manual. 2) Purchase the Monster Manual as a whole. 3) Homebrew the Smoke Mephit yourself from another copy of the MM you own by using the homebrew system on D&D Beyond.
Im trying to homebrew an archtype by giving it a elemental beast companion. It let me add the magma mephit but not the smoke mephit.
I doubled check to make sure all the same boxes were the some still will not come up as and option.
The Magma, Steam, Ice, and Dust mephits are available for free as part of the Basic Rules. The Smoke Mephit is a part of the Monster Manual. You would need to either:
1) Purchase the Smoke Mephit individually from the Monster Manual.
2) Purchase the Monster Manual as a whole.
3) Homebrew the Smoke Mephit yourself from another copy of the MM you own by using the homebrew system on D&D Beyond.
Thank that helps so much.