Software for Nokia N95

Newbie here so apologies if there is somewhere better I should post or
if this subject is repeated every month.

I have an N95 (not 8GB) on O2 but updated with the latest generic software.

I am interested in trying out some freeware or possible low cost if
really good.

Any advice on the best place to find suitable software?

Any advice on the best way to hack the phone so it can install unsigned
software? It appears all ways of self signing have now been blocked

I have tried one or 2 things but would appreciate some advice before I
mess up my phone.

TIA for any advice.