Of Frogs and Roses
Only tweak needed so far, is a tweak of spell list. Most notable is the removal of the Eldritch Blast Cantrip and similar Evocation spells. Instead a bunch of other spells will be added, probably each Patron will come with a larger list of spells.
All Warlocks suffers from effects “leaking” through from the Patreon, these are mostly roleplay effects and hooks for me as a DM.
Examples of alternate patreons:
Heaven this could be an alternative manifestation of Sol Invictus, a heretic? A saint? Perhaps this is was who lead Jean d’Arc?
The Crone is perhaps the opposite from the Heaven patreon delving in to forces of the earth and chaos rather than heaven and law.
The Earthmother , is probably what the druids was or become after the Arcadians (Romans) exterminated them.
From the massive Codex: Unearthed Arcana: The Hexblade, The Raven Queen and The Seeker all three are easy to find roles for in Dark Albion. Undying Light needs tweaking due to the focus on evocation magic..
This could be another heretical Sol Invictus sect, or something all together different: Sun Mover.
An alternative to the General Outer Gods would be the Defiler.