This was an amazing time! Congratulations to all participants -- what an accomplishment - - and very heartfelt THANK YOU to Donna and Abbie!
Abbie, you mentioned you are looking for ideas for future challenges. For what it's worth (and as a challenge addict) I did some brainstorming ...
I missed some of the shorter challenges you put forth this past year, so forgive me if any of these suggestions have already been done, but, some possibilities that come to mind: sports related (either all encompassing or smaller ones by specific sport or athletic activity); motor vehicles, holiday or special day-related themes (Valentines Day, 2023 Year of the Rabbit, St Patrick's Day, birthdays, anniversary, etc.); under the sea (sea creatures and plants) -- maybe under and over the sea; boats; talisman and/or good luck charms; superstitions; images meant for children/younger generation; Night skies (stars, planets, universe, galaxies); cityscapes; seascapes; landscapes; handscapes (probably won't work for straight photography), zentangles (also, likely will not work for straight photography); animals (either global or specific); kites and windy day activities; trains; theme parks (rides / games / food); travel related; space aliens; musical instruments; candles and soft light; merry-go-rounds; camping; types of buildings/dwellings (barns, churches, movie theater buildings and their marquees, houses, tents, yurts, teepees, animal dwellings? etc); games and/or game-related that wouldn't violate trademark or have other legal complications; quenching one's thirst / beverage related; bridges; aircraft; and ... ? ? ? ?