Yep, you've found them all.
As far as this spell lacking versatility is concerned, remember that versatility is not the only measure of power. (Power is power.) For example, the 6th-level spell Planar Ally can summon pretty much anything, but the caster has no control over it whatsoever. Going outside of the Cleric spell list, the 7th-level spells Mordenkainen's Sword or Finger of Death are both entirely without versatility.
Conjure Celestial, on the other hand, is reliable and controllable. As far as versatility is concerned, one of the creatures you can summon is the Couatl. The Couatl has 14 different spells, almost all of which it can use multiple times per day. It can also use its Change Shape ability to turn into a bunch of other things. In fact, the Couatl is so ridiculously versatile that I'd argue that it inherently makes Conjure Celestial a well and truly versatile spell.