This is the easiest mono-god list I've ever written, mostly as it falls right into my "stick anti-tank anywhere" philosophy.
Mono-Tzeentch, 1996 pts
HQ
Chariot of Tzeentch, Bolt, WaL, MoS 110
Chariot of Tzeentch, Bolt, WaL, MoS 110
Chariot of Tzeentch, Bolt, WaL, MoS 110
Chariot of Tzeentch, Bolt, WaL, MoS 110
Elites
5 Flamers, Bolt 205
5 Flamers, Bolt 205
5 Flamers, Bolt 205
Troops
5 Pink Horrors, Changeling, Bolt 100
5 Pink Horrors, Bolt 95
5 Pink Horrors, Bolt 95
Fast Attack
3 Screamers, 48
3 Screamers, 48
Heavy Support
Soul Grinder, Phelgm, Tongue 185
Soul Grinder, Phelgm, Tongue 185
Soul Grinder, Phelgm, Tongue 185
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As we don't have a whole lot of choice in each slot, it's inevitable to spam whatever unit it is. Good thing Tzeentch has some good units!
Every single unit in this army can kill a tank. Even then, it has less firepower than most Marine armies. Go figure.
Mobility is your friend in this list, careful placement of units will make or ruin you: keeping the grinders back until all the melta is dead, then rushing them in once they are silenced is key to the list. Dropping the Grinders safely is particularly challenging, so you might want to cut out some screamers to put an icon on one of the Horror squads.
5 flamers, with breath of chaos, will destroy nearly any unit in the game in one shot. But again- be careful.