This is a 68 card partial deck. I have many 32 card sub-decks (one for each tribe, for example, Drakes). I add (swap in) one of these sub-decks to this 68 card partial deck, to make a complete 100 card EDH deck.
The sub-decks are usually 21 creatures, 5 spells, 5 lands, and 1 mana acceleration. So the complete 100 card deck is usually 28 creatures (counting the general), 28 spells, 36 lands, and 8 mana acceleration.
For ease of swapping, I put a little sticker of a star on the lower left corner of each card of the sub-decks, so I can quickly find them and pull them all out.
Some of the sub-decks (the larger tribes) have 38 cards instead of 32 (an extra 6 creatures). In this case, I remove the 6 creatures from this deck.
I made these decks "modular" because my tribal decks had so many cards in common. I experimented with 50+50 cards, 70+30 cards, then finally settled on this 68+32 card setup. It also allows me to potentially carry a very large number of decks in one long box. I'm always surprised at how differently the decks play, considering 68 of the cards are the same.
I (somehow) got into the habit of swapping out the Sol Ring for an Oblivion Stone sometimes, depending on my impression of the play group / environment. I realize this is the not the most logical two cards to swap (one mana card for one non-mana card), but I've been doing it for a while, so I thought I'd mention it.