Cast Chain of Smog by paying {1}{B}, targeting yourself.
Dragonsguard Elite triggers, putting a +1/+1 counter on it.
Resolve Chain of Smog, causing you to discard two cards and copy Chain of Smog, targeting yourself.
Repeat from step 2.

Infinite +1/+1 counters on a creature

Infinite magecraft triggers

Chain of Smog

Dragonsguard Elite

Cast Chain of Acid by paying {3}{G}, targeting an indestructible noncreature permanent you control.
Dragonsguard Elite triggers, putting a +1/+1 counter on it.
Resolve Chain of Acid, destroying nothing and causing you to copy Chain of Acid, targeting an indestructible noncreature permanent you control.
Repeat from step 2.

Chain of Acid

Activate Dragonsguard Elite by paying {4}{G}{G}, doubling the number of +1/+1 counters on it.
Activate Blade of Shared Souls's equip ability by paying {2}, attaching it to Dragonsguard Elite.
Blade of Shared Souls triggers, making Dragonsguard Elite become a copy of Ramos for as long as the equipment is attached to it.
Activate Dragonsguard Elite using Ramos's ability by removing five +1/+1 counters from it, adding {W}{W}{U}{U}{B}{B}{R}{R}{G}{G}.
Activate Blade of Shared Souls's equip ability by paying {2}, attaching it to any creature besides Dragonsguard Elite and ending the copy effect.
Blade of Shared Souls triggers; decline to use its ability.
Repeat.
Once there are infinite +1/+1 counters on Dragonsguard Elite, you may repeat the loop from step 2 infinite times, adding infinite mana.

Infinite +1/+1 counters on certain creatures

Infinite colored mana

Ramos, Dragon Engine

Blade of Shared Souls

Mirror Box

Cast Mimeoplasm by paying {4}{B}{G}{U}
As Mimeoplasm enters, exile Ramos, Dragonsguard Elite, and two additional creature cards from your graveyard, causing Mimeoplasm to enter with twelve +1/+1 counters on it.
Activate Mimeoplasm by paying {2}, causing it to become a copy of Ramos with this ability.
Activate Mimeoplasm using Ramos's ability by removing five +1/+1 counters from it, adding {W}{W}{U}{U}{B}{B}{R}{R}{G}{G}.
Activate Mimeoplasm by paying {2}, causing it to become a copy of Dragonsguard Elite with this ability.
Activate Mimeoplasm using Dragonsguard Elite's ability by paying {4}{G}{G}, doubling the number of +1/+1 counters on it.
Repeat from step 3.

Mimeoplasm, Revered One

Activate Necrotic Ooze using Dragonsguard Elite's ability by paying {4}{G}{G}, doubling the number of +1/+1 counters on Necrotic Ooze.
Activate Necrotic Ooze six times using Crystalline Crawler's first ability by removing six +1/+1 counters from Necrotic Ooze, adding {4}{G}{G}.
Repeat.

Crystalline Crawler

Necrotic Ooze

Activate Necrotic Ooze, doubling the +1/+1 counters on it to 14 +1/+1 counters.
Remove six +1/+1 counters from Necrotic Ooze to add {6}.
Repeat.

Combos with "Dragonsguard Elite"