18 cards where the color identity ≤ BGU and the text includes “spore counter”

Deathspore Thallid (Time Spiral Remastered #109)
Elvish Farmer (Masters Edition II #156)
Feral Thallid (Masters Edition II #161)
Fungal Bloom (Masters Edition II #165)
Propagator Primordium (Alchemy: Ixalan #20)
Psychotrope Thallid (Planar Chaos #137)
Savage Thallid (Time Spiral #213)
Spore Flower (Masters Edition II #177)
Sporesower Thallid (Time Spiral Remastered #231)
Sporoloth Ancient (Time Spiral Remastered #232)
Thallid (Modern Masters #167)
Thallid Devourer (Masters Edition II #181)
Thallid Germinator (Time Spiral Remastered #236)
Thallid Shell-Dweller (Time Spiral Remastered #237)
Thelon of Havenwood (Time Spiral Remastered #238)
Thorn Thallid (Masters Edition #135)
Utopia Mycon (Time Spiral Remastered #244)
Vitaspore Thallid (Planar Chaos #143)

This search is finished. Now the real work can begin.