Can confirm, it is the only maintained one on the main repo, I guess the other ones will get there eventually.
"rant" incoming
I must say, I get the impression (not backed by any data) that the mere existence of IzzyOnDroid's repo slows down the porting process of several apps to the main repo, because with the fact that it is more lax on the requirements while still being accessible through the usual F-droid apps, devs can do the bare minimum to get it on there and close the ritual "Add to F-droid" issue, so it creates an excuse for developers to postpone even further the efforts to fit their apps to the strict requirements of actual F-droid.
They don't get any incentive to do it actually, because most F-droid (app) users will also be adding Izzy's repo since it's so full with the latest open source apps, effectively watering down the main repository, the only thing is that Izzy limits the size each package can take up, so if it's too big it will have to go to another repo, be it self-hosted or the main one.
All of that said, I have nothing but respect for Izzy as he does a lot to get at least the F-droid inclusion started at all, roping in the devs of a myriad of apps scattered across GitHub and explaining what they need to do must be pretty tiring, so props to him