The best replacement for thermal paste is thermal pad.

The best alternatives to thermal paste are rated as following:
★★★★★  thermal pad
★★★★  thermal compound
★★★  thermal grease
★★★  no thermal paste
★★  toothpaste
★★  pad
★  thermal adhesive
★  thermal tape
★  dielectric grease
★  solder
★  arctic silver
  thermal pads

Your alternative for thermal paste is not listed? Suggest!
Speaking about thermal paste, one probably shouldn't forget about heatsink.

Other search terms related to thermal paste and their ratings are:
★★★★★ heatsink
★★★★ hyper 212 evo
★★ corsair h80
★ hyper 212
You have in mind a companion for thermal paste and it is not yet here? Propose!



Google Trends

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thermal paste
thermal pad
thermal compound