The next mechanic is Warp
Idris, Soul of the TARDIS lets you do this with Basalt Monolith and Heartstone, but theres a lot of fun (for you) if you throw Mindslaver into the mix
While Fate Reforged was the last set that delve headlined, Wizards has continued experimenting with the mechanic over the years, particularly in sets with higher power levels
While youre not guaranteed to pull anything by opening loose packs, you can customize exactly how many packs you want or how much youre willing to spend at a given time, making these the most flexible option for any collector
Getting stuff to leave your graveyard isnt a huge ask in the format either, as the entire Collect Evidence mechanic is all about doing that
For five mana you get a tapped mana rock that you take a turn off from, then it taps for five mana, so it's the rare mana rock that taps for the same mana as that making it