How do you call this kind of black insulating tape?

[hexaae]

How do you name it and where can you find these kind of insulating/thermal films covering RAM and NVMe in some laptops?

[pndiode]

Kapton tape or Black Kapton tape.

https://kapton-tapes.com/

Just do a search for:  Kapton tape.

It could be a Polyimide tape too, but I will lean toward Kapton tape. 

Polyimide Tape and Kapton Tape | Strouse

[hexaae]

I used Kapton adhesive tape in the past but these are different: the only adhesive part is on top and it looks more like a smooth plastic sheet Post-It like...

[pndiode · Accepted solution]

Graphite Tape
Graphene Tape

High Thermal Conductivity Heat Dissipation Sticker For Cooling Gpu Cpu - Buy Heat Dissipation Sticke...

[hexaae]

Yeah, must be that! Thank you