Caido[1] a interception proxy written in Rust, is positioning itself as a "lightweight" alternative to Burp. It can't compete yet with Burp in terms of functionality, although the product is certainly looking promising.
Perhaps the only contender to Burp in respect to functionality/features is ZAP[2].
EDIT: You can run your own collaborator type setup with Project discovery's interactsh[3].
Further EDIT: A downvote might be because of the mention of Rust / closed source - this is explicitly mentioned because a large pain point for Burp is it's a Java memory hog. If Caido was written in C++ with Qt, this fact would be notable for the exact same reason.