We did a few:
Tower of the Wise
Legendary Land
Whenever a spell is countered, remove all wisdom counters from Tower of the Wise and put a number of wisdom counters on it equal to the converted mana cost of the countered spell.

: Add

to your mana pool for each wisdom counter on Tower of the Wise.
Soul Chasm
Land
At the end of any turn, put a soul counter on Soul Chasm if one or more creatures were put into your graveyard from play that turn.

: Add

to your mana pool for each soul counter on Soul Chasm.
Volcanic Peak
Land
When you attack with one or more creatures, put a fury counter on Volcanic Peak.

: Add

to your mana pool for each fury counter on Volcanic Peak.