From the homepage, you can put in a card and find any combos that use it, or you can use the advanced search to look for combos by anything from a specific outcome, the colour identity of your commander, or even how many cards are needed to pull it off
Then you'll add that mana too - this is an essential for Spellslinger brews since it will trigger your Guttersnipes and such too, unlike dorks that recur
Or, if we can get Beast - Relentless to stick to the board, we can combo off with him in one turn with our multiple ping effects
World Map Rating: 2/10 There are probably no lands good enough that its worth putting 3 mana into World Map, but Traveler's Amulet is a perfectly reasonable way to fix your mana and so is this
Another great choice is Craterhoof Behemoth which gives your team a massive +X/+X boost and trample from your creature count, making your Elf swarm lethal