The custom variables option is still available, but there's an important requirement: any custom variables you use in Clay must already be added to the campaign in Instantly via an import first. [1]
Due to limitations in the Instantly API, you can't create new custom variables directly from Clay - they need to exist in your Instantly campaign already. Try importing your custom variables into your Instantly campaign first, then they should appear as options in Clay.
Hi Peter, I am so sorry for the earlier issue with dropdown options not appearing in some sequencer tools such as Instantly, Lemlist, and HeyReach. Happy to report that we heard back from the team and this issue should be fixed.
Try a quick refresh (Cmd/Ctrl + Shift + R) and let us know if the problem has been resolved on your end, or if you still have trouble.