Avacyn Restored gave us a lot of angel and demon tokens if you opened the Helvault. Also, you could get a double-faced human/wolf tokoen at FNM.
A few Duel Decks give out free tokens too:
Ajani v. Nicol Bolas had a griffin token and a saproling token. (Ajani's deck is a soul sisters variant that uses various incremental lifegain spells to trigger Searing Meditation .)
Knights v. Dragons had some goblin tokens. (They're the dragon deck's main weenies, and, along with Fire-Belly Changeling , make great Voracious Dragon chow. Sadly, the product's still imbalanced as all hell by how top-heavy the dragon deck is.)
Elspeth v. Tezzeret had soldier tokens.
Phyrexia v. the Coalition had hornet, minion, and saproling tokens. ( Phyrexian Processor is really good, and saproling tokens are kind of a thing for the Coalition.)
Garruk v. Liliana had two separate beast tokens and an elephant token.
Jace v. Chandra had an elemental shaman token. (Yep, even in the two least creature-focused colors, and red technically doesn't even need creatures to win, there's a token.)
Finally (firstly?), Elves v. Goblins had a goblin, an elf warrior, and an elemental token.
Other than that, mostly packs. They've been doing it since like, Tenth Edition. Before that, just promos and Unglued.