Summon stuff

[Dmdork]

Conjure Celestial seems cool. Does the DM choose which one comes or can the player choose? If so, what are some good CR4 celestials?

[OgataiKhan]

Conjure Celestial seems cool. Does the DM choose which one comes or can the player choose? If so, what are some good CR4 celestials?

It is unclear whether the DM chooses what is summoned since the Sage Advice about it only talks about spells that let you choose a CR, like Conjure Animals.

In any case your only options in the Monster Manual are the Pegasus (CR 2), the Couatl (CR 4), and the Unicorn (CR 5—requires spell slot 9), so this spell might as well be called "Conjure Couatl". But that's great, Couatls are awesome! They are powerful, difficult to kill spellcasters who can turn into any humanoid or beast with a CR of 4 or lower, which opens the door to all kinds of shenanigans.