About a year ago I downloaded an inferior game that was more of a direct sequel to Lords of Chaos called Chaos Reborn. This game had the same basic principle (it's just a mess in so many ways) but one thing that it had, which might fit here, were staffs you could equip with runes that would give bonuses to certain races, alliances, flying, or melee, evil, or good, etc...
Chaos Reborn is from Julian Gollop, the original creator of Chaos and Lords of Chaos. It came out the same year I released Last Warlock - but obviously got a lot more attention than Warlock due to the fame of the creator (plus of course, it has nicer artwork!) I had supported the Kickstarter but upon playing it, it wasn't what I was looking for, and I didn't play it for very long. Can you elaborate more on how the runes are acquired, or changed by players?
All 'Warlocks' have a staff and different staffs have different rune slots which dictate what kind of runes, and ultimately, what kind of deck works best with that particular staff and runes. As a hypothetical example, a basic staff has 2 rune slots, a circle rune and a square rune. The circle runes pertain to Warlock buffs, such as bonus ranged if adjacent an elf ally a square rune involves creature summoning, such as if all allies are elves, good, undead, animals etc... then they would receive a bonus.
I'm not suggesting you implement their convoluted design but I would love to see synergies and rewards for creating theme based decks, whether that theme is: melee, ranged, race, or alignment focused. It could even be done with special abilities, as there is currently a small synergy between goblins and wolves, but there's not further incentive to keep going down either an animal or a goblin path.
As for how they're unlocked, I don't remember exactly, but it wasn't great. I think you spent an in game currency to buy packs which contained a number of random runes and/or staff.