Does Toxic count as a separate source of poison counters from infect?

Toxic and Infect are two distinct keyword abilities, each defined separately in the Comprehensive Rules. Infect (CR 702.90) causes a creature to deal damage to players in the form of poison counters (1 damage = 1 poison counter) instead of loss of life. Toxic (CR 702.164) causes a creature to give an additional number of poison counters equal to its Toxic value whenever it deals combat damage to a player.

Because they operate through different mechanisms, a creature with both Infect and Toxic does not simply add the two numbers together in a straightforward way. Infect replaces the damage-as-life-loss with damage-as-poison-counters, so a 2/2 with Infect dealing combat damage gives 2 poison counters via Infect. Toxic then adds its bonus on top. So a 2/2 with Infect and Toxic 1 would give 2 (from Infect) + 1 (from Toxic) = 3 poison counters total.

Crucially, Toxic alone (without Infect) still deals normal combat damage to the player's life total AND ALSO gives poison counters equal to the Toxic value. Infect alone replaces all damage with poison counters. They are sourced from different rules triggers and are not redundant — they each fire independently.

Example: A 3/3 creature with Toxic 2 (but no Infect) attacks and deals combat damage to a player. That player loses 3 life (normal damage) AND receives 2 poison counters from Toxic. If that same creature also had Infect, the player would lose 0 life but receive 3 poison counters (from Infect replacing damage) plus 2 more from Toxic, totaling 5 poison counters.

So yes, they are separate sources of poison counters governed by different rules (CR 702.90 for Infect, CR 702.164 for Toxic), and a creature with both will generate poison counters from each ability independently.