What about dual lands with the clause "you may not search your library for land cards". This would allow an additonal set of Duals at the cost of not being able to run fetches.
I don't think anything can replace fetches in eternal formats. Filling your graveyard + shuffling is too good. Indestructible duals seem good, but not good enough I guess.
There are also options like the new Thriving cycle (like Thriving Isle), if they came into play untapped.
@desolutionist I'd play those....cuz fu*k wasteland.
Indestructible dual lands could replace fetches.
Like Ravnica duals with indestructibility. Maybe not count as forest, plains, swamp, etc. but just be “Land”