Up to The d20 System
When I DM’d 3e, I used simple initiative cards. (The more complex cards slowed me down rather than speeding me up.) Each PC & each monster (or monster group) has a card. They are stacked in initiative order. Actions that change a combatant’s place in the initiative order moves their card in the deck. Lasting effects get a card with a duration to be decremented each round.
This system was borrowed from Bradd Szonye. Here are links to posts about Bradd’s system and related topics: