Activate Thranduil using Immaculate Magistrate's ability by tapping it, putting a +1/+1 counter on Thranduil for each Elf you control.
Activate Thranduil using Devoted Druid's second ability by putting a -1/-1 counter on it, untapping it.
Repeat.

Infinite +1/+1 counters on creatures you control

Infinite green mana

Thranduil, the Elvenking

Devoted Druid

Immaculate Magistrate

Activate Thranduil using Timberwatch Elf's ability by tapping it, giving Thranduil +1/+1 until end of turn for each Elf you control.
Activate Thranduil using Devoted Druid's second ability by putting a -1/-1 counter on it, untapping it.
Repeat.

Infinitely large creatures you control until end of turn

Timberwatch Elf

Activate Thranduil using Greenhilt Trainee's ability by tapping it, giving Thranduil +4/+4 until end of turn.
Activate Thranduil using Devoted Druid's second ability by putting a -1/-1 counter on it, untapping it.
Repeat.

Greenhilt Trainee

Activate Thranduil using Woodland Weavemaster's ability by tapping it, adding an amount of mana equal to Thranduil's power that can only be spent to cast Elf spells or activate abilities of Elves.
Activate Thranduil using the ability granted to it by Umbral Mantle by paying {3} and untapping it, giving it +2/+2 until end of turn.
Repeat.

Infinite colored mana that can only be spent to activate abilities of certain creatures

Infinite colored mana that can only be spent to cast spells of a certain creature type

Infinitely large creature until end of turn

Umbral Mantle

Woodland Weavemaster

Activate Thranduil using Tromell's ability by tapping it, putting a +1/+1 counter on Thranduil for each nontoken creature that entered under your control this turn.
Activate Thranduil using Devoted Druid's second ability by putting a -1/-1 counter on it, untapping it.
Activate Thranduil using Devoted Druid's first ability by tapping it, adding {G}.
Activate Thranduil using Devoted Druid's second ability by putting a -1/-1 counter on it, untapping it.
Repeat.

Combos with "Thranduil, the Elvenking"