Yarbo’s own is preferred. There is a document in their Support KB outlining the properties of the grease they require: Yarbo’s track lubrication information
On FB there has been discussion of people using other silicone-based greases:
- Super Lube (available at Home Depot) Silicone Dielectric Grease (and other similar ones)
- EDSRDUS (or similar spelling) High Vacuum Grease
- OAIEGSD Silicone Paste
Whatever you go with, make sure it meets the requirements in Yarbo’s support KB document.