Hi, I am the OP from the other thread. I found a few symbols that you might like, mostly from the Greek alphabet which is widely adopted on various platforms.
⫓
Subset Above Superset U+2AD3
This is character is not from the Greek alphabet, so I am not too sure about compatibility but it works on android and windows.
ẟ
Latin Small Letter Delta U+1E9F
I think this might be one of the more popular choices among the community, not just because of its design but delta character in uppercase is
Δ
which is probably going to be the unicode symbol for the Safenet itself. A nice coincidence if picked.
ϑ
Greek Theta Symbol U+03D1
I picked this because it would be my personal choice, but I think that the community should be the ones to choose.
Please comment to say which one you would prefer or make your own suggestions.