There have been a number of patron variants that are blocked due to difficulty or due to requiring a champion that is normally blocked for that patron. However, as the Tales campaign shows it is technically possible to have a blocked champion enabled as a special case. Additionally the addition of Baldric has created a situation where even in a "no champions allowed" scenario the DM -> Baldric -> Dwarves chain allows for a decent sized formation. Notably the recently released variants did allow the Mirt variant of "Frozen Dessert in the Desert" which is a "no champions allowed" combination.
So given that I'd like to see all Patron variants enabled (with possibly one exception).
These variants are only blocked due to requiring a specific champion which seems to no longer be a technical issue:
Taking Responsibility - Mirt and Vajra
Force Grey Unleashed - Strahd
A Hitch in the Mortuary - Elminster
These variants are blocked due to limited champion availability, but as I said I think they should be doable now with DM, Baldric and other cheating champions:
And a Pixie in a Pear Treant - Vajra
Shadow Stalkers - Zariel
Wyld Stallyns - Elminster (this one may be a mistake since other similar Elminster variants are enabled)
So finally we come to the one possible exception - the Mirt variant of Twice Through the Great Wheel. I do actually think that this is doable (with one caveat), it should be possible for Wren and Dark Urge to clear the 301-400 section and use DM, Baldric and Dwarves to clear the 701-800 section. However, this does run into the problem that there's no way to tell what seat DM is going to hit until you hit 701 which would be very frustrating, so might need to leave this out or make it so that you can swap champions in Zone 1 to let people check DM at the start.