mono_crash hidden files in home directory
There is no problem on removing them.
They were created by some application developed with Mono. When the application crashes, it dumps the memory content into those .blob files. Take a look at your .json file and you might find which application to blame. I also happened to find in my home folder some of them and they were created by gnome-subtitles. Check it out:
$ grep thread_name mono_crash.c0a5b8e87.0.json
"thread_name" : "gnome-subtitles",