Usually, a selection of Multiplayer maps and at least one Zombies map.

While there is no permanent "free" version of the full series for PC or consoles, you can legally play large portions of the franchise for free through specific trials and standalone modes. 1. Official Free-to-Play Titles

These games are permanently free to download and include mechanics or maps from the Black Ops universe.

Most modern titles are now accessed through Call of Duty HQ , which you can download for free to then install specific trial packs. 3. Subscription Services (Xbox & PC)

A massive free-to-play battle royale. It often features "Black Ops Royale" modes and maps like Avalon or Area 99 inspired by the Black Ops series.