I fell to my death and now I can't find them either.
If you have died and don't have any items then there is no way to find your base other than looking at the world data files, because there is nothing in the game that will point you at “a place where I built a bunch of stuff previously”.
In that case, you can go to your world spawn point and search outward from there — try to look for familiar terrain you might have traversed to get to your base location.
If your base has a Nether portal, then conducting a search can be easier, since distances are much shorter — but the Nether is more dangerous to traverse, and a portal might be easily hidden on the other side of some terrain if you haven't extensively built paths from it.
On the other hand, if you're preparing for getting lost while still having your items, then the best option for consistently finding your way home is a compass tied to a lodestone in your base, since it will point the correct direction no matter how far away you are.
Maps can also be useful — for more than just the area they cover, because if you're outside the map's coverage area but still somewhat in the area, a dot will be displayed on the border of the map showing which side of the map you're past. I believe the dot eventually disappears if you're far enough away, though. Remember that maps can be "zoomed out" by combining them with paper on a cartography table; this makes them show a larger area. Also, if you duplicate a map then all the copies will show the same contents even after mapping more area, so keeping a copy safe ensures your mapping work isn't lost if you die with one of the copies.