Born to Drive and Nurturing Presence attached to Devoted Druid.
Devoted Druid does not have summoning sickness.

Activate Devoted Druid by tapping it, creating a 1/1 Elf Warrior creature token.
The Elf Warrior enters the battlefield, triggering Devoted Druid, giving Devoted Druid +1/+1 until end of turn.
Activate Devoted Druid's second ability by putting a -1/-1 counter on it, untapping it.
Repeat.

Born to Drive and Nurturing Presence attached to Barrenton Medic.
Barrenton Medic does not have summoning sickness.

Activate Barrenton Medic by tapping it, creating a 1/1 Elf Warrior creature token.
The Elf Warrior enters the battlefield, triggering Barrenton Medic, giving Barrenton Medic +1/+1 until end of turn.
Activate Barrenton Medic's second ability by putting a -1/-1 counter on it, untapping it.
Repeat.

Elemental Mastery and Nurturing Presence attached to Devoted Druid.
Devoted Druid does not have summoning sickness, and has a power of one or greater.

Activate Devoted Druid by tapping it, creating at least one 1/1 Elemental creature token with haste.
When the Elemental token(s) enter the battlefield, Devoted Druid triggers that many times, giving it +1/+1 until end of turn for each creature that entered the battlefield.
Activate Devoted Druid by putting a -1/-1 counter on it, untapping it.
Repeat.
If Devoted Druid has a power of two or greater, Devoted Druid becomes infinitely large until end of turn, which allows you to use its mana ability instead to get infinite .

Elemental Mastery and Nurturing Presence attached to Barrenton Medic.
Barrenton Medic does not have summoning sickness, and has a power of one or greater.

Activate Barrenton Medic by tapping it, creating at least one 1/1 Elemental creature token with haste.
When the Elemental token(s) enter the battlefield, Barrenton Medic triggers that many times, giving it +1/+1 until end of turn for each creature that entered the battlefield.
Activate Barrenton Medic by putting a -1/-1 counter on it, untapping it.
Repeat.
If Barrenton Medic has a power of two or greater, it also becomes infinitely large until end of turn.

Elemental Mastery and Nurturing Presence attached to Cinderhaze Wretch.
Cinderhaze Wretch does not have summoning sickness, and has a power of one or greater.

Activate Cinderhaze Wretch by tapping it, creating at least one 1/1 Elemental creature token with haste.
When the Elemental token(s) enter the battlefield, Cinderhaze Wretch triggers that many times, giving it +1/+1 until end of turn for each creature that entered the battlefield.
Activate Cinderhaze Wretch by putting a -1/-1 counter on it, untapping it.
Repeat.
If Cinderhaze Wretch has a power of two or greater, it also becomes infinitely large until end of turn.

Born to Drive and Nurturing Presence attached to Cinderhaze Wretch.
Cinderhaze Wretch does not have summoning sickness.

Activate Cinderhaze Wretch by tapping it, creating a 1/1 Elf Warrior creature token.
The Elf Warrior enters the battlefield, triggering Cinderhaze Wretch, giving Cinderhaze Wretch +1/+1 until end of turn.
Activate Cinderhaze Wretch's second ability by putting a -1/-1 counter on it, untapping it.
Repeat.

Splinter Twin and Nurturing Presence attached to Barrenton Medic.
Barrenton Medic does not have summoning sickness.

Activate Barrenton Medic by tapping it, creating a token copy of itself with haste.
When the Barrenton Medic token enters the battlefield, the nontoken Barrenton Medic triggers, giving itself +1/+1 until end of turn.
Activate Barrenton Medic by putting a -1/-1 counter on it, untapping it.
Repeat.

Splinter Twin and Nurturing Presence attached to Devoted Druid.
Devoted Druid does not have summoning sickness.

Activate Devoted Druid by tapping it, creating a token copy of itself with haste.
When the Devoted Druid token enters the battlefield, the nontoken Devoted Druid triggers, giving itself +1/+1 until end of turn.
Activate Devoted Druid by putting a -1/-1 counter on it, untapping it.
Repeat.
Optionally, you may use the mana abilities of the Devoted Druid tokens to add infinite .

Splinter Twin and Nurturing Presence attached to Cinderhaze Wretch.
Cinderhaze Wretch does not have summoning sickness.

Activate Cinderhaze Wretch by tapping it, creating a token copy of itself with haste.
When the Cinderhaze Wretch token enters the battlefield, the nontoken Cinderhaze Wretch triggers, giving itself +1/+1 until end of turn.
Activate Cinderhaze Wretch by putting a -1/-1 counter on it, untapping it.
Repeat.