If you loved Fairy Tail: Dragon Cry, try Trinity Seven: Eternity Library & Alchemic Girl
A bridge between a film you've already seen and one most people haven't. Trinity Seven: Eternity Library & Alchemic Girl has roughly 6.8× fewer votes than Fairy Tail: Dragon Cry — it's a deeper cut, not a mainstream recommendation. Here's what they share, and what the second one does that the first one doesn't.

Fairy Tail: Dragon Cry

Trinity Seven: Eternity Library & Alchemic Girl
What they share
Theyboth carry the playful mood tag, and they sit in Action / Animation / Comedy / Fantasy territory. If that's the register that drew you to Fairy Tail: Dragon Cry, the second film will land in a comparable space — through a different lens.
What Trinity Seven: Eternity Library & Alchemic Girl is
Here's one for the "anime fans only" shelf. Our hero accidentally conjures a precocious child, Lilim, from a magic book, which also awakens the dreaded White Demon Lord. Cue the final battle, so our heroes can save the world, again.