Sol Ring

Yoshimaru, Ever Faithful

Whenever another legendary permanent you control enters, put a +1/+1 counter on Yoshimaru, Ever Faithful.
Partner (You can have two commanders if both have partner.)

Wood Elves

When Wood Elves enters, search your library for a Forest card, put that card onto the battlefield, then shuffle.

Dryad Arbor

(Dryad Arbor isn't a spell, it's affected by summoning sickness, and it has "{T}: Add {G}.")

Green Sun's Zenith

Search your library for a green creature card with mana value X or less, put it onto the battlefield, then shuffle. Shuffle Green Sun's Zenith into its owner's library.

Nature's Lore

Search your library for a Forest card, put that card onto the battlefield, then shuffle.

Three Visits

Search your library for a Forest card, put it onto the battlefield, then shuffle.

Jedit Ojanen, Mercenary

Whenever Jedit Ojanen, Mercenary or another legendary creature you control enters, you may pay {G}. If you do, create a 2/2 green Cat Warrior creature token with forestwalk. (It can't be blocked as long as defending player controls a Forest.)

Yavimaya, Cradle of Growth

Each land is a Forest in addition to its other land types.

Niambi, Faithful Healer

When Niambi, Faithful Healer enters, you may search your library and/or graveyard for a card named Teferi, Timebender, reveal it, and put it into your hand. If you search your library this way, shuffle.