Abiotic Factor

Microtransactions in Abiotic Factor are summarized as...

There are no microtransactions or extra purchases. At this time there is no paid DLC, but the developers have stated there are plans for premium DLC. There are no details on pricing, frequency, or anything else.

In their own FAQ they list the following:
Will the game have microtransactions? Nope! If you purchased the game you have access to everything inside of it, barring a few unlockable treats via gameplay. No premium currencies or paywalled content is planned, though we do have plans for premium DLC down the line. All pricing information for extra content will be laid out clearly as we get closer to release – no surprises.
There are no microtransactions or DLC, but there are plans for DLC later down the line.