Very customizable (I like having number row always visible, and having long press for symbols on each letter).
Has gif support built in.
My biggest pain point is:
It auto corrects words that are spelled correctly to other words. I type "our" and it changes to "out", I recently typed "purpose" and it changed it to "purple". Autocorrect is awesome and necessary, but I hate that it corrects words to other words and not just typos. I wish I could find a keyboard that has the things I like without this annoyance.
OpenBoard. Has what I need in terms of customization and I can turn off word prediction/correction (not sure if it even has it to begin with). Used to use Swiftkey several years ago but i like OpenBoard more nowadays.
I like correction of typos and prediction, I just don't like correcting words into other words. I haven't found a way to have one without the other. Correct me if I'm wrong.