Free Archetype Variant
Archetypes in Starfinder allow a player to craft a specific character concept that goes beyond a theme and class, granting specific abilities that are usually unavailable through those means. However, the alternate class features offered by an archetype alter or replace the main features of a class at certain levels. Sometimes, the story of a particular campaign calls for characters who are part of the same organization or who have a shared background. The free archetype variant introduces a way to make such characters while retaining existing class features.
Gaining a Free Archetype
The differences between a regular character and a free-archetype character begin when the character reaches 2nd level (or the first level at which that archetype provides an alternate feature). At that point, the player should choose an archetype their character meets the prerequisites of (if any) to gain that archetype’s first alternate class feature for free, in addition to gaining any of the normal features of their class. While using this system, you treat a PC’s character level as their class level for the purposes of archetype selection and abilities. As the character levels up, they continue to gain that archetype’s alternate class features (at 4th, 6th, 9th, 12th, and/ or 18th levels) without having to alter or replace their normal class features. If the archetype offers a choice of alternate class features at a particular level, the player can make that choice freely but must still choose an alternate class feature they qualify for. If an archetype doesn’t offer an alternate class feature at a particular level, the player gains a bonus feat instead (they must still meet the prerequisites for that feat).
Depending on the campaign, the GM might restrict the archetypes that can be chosen, perhaps even to a single archetype (such as the phrenic adept for a group that has experienced a shared psychic awakening).
Unlike a normal archetype, this free archetype isn’t attached to a particular class, so a player can multiclass and continue to advance in their chosen free archetype. A player can also add different archetypes to their character as normal.
The Free Archetype Variant in Play
Free-archetype characters are a bit more powerful than regular characters, as they have access to more versatile abilities, but this is unlikely to unbalance the game. These additional options might be overwhelming to newer players, so a GM might want to consider limiting the use of regular archetypes when using this variant, so as not to introduce more complexity.
If a character retrains skill ranks or feats using the retrain downtime activity (Character Operations Manual 155) and no longer meets the prerequisites for a free archetype, the character loses access to all of that archetype’s abilities until they meet the prerequisites once again.
Source
Starfinder Enhanced pg. 185