.WAV Audio enhancement/restoration

hi everyone.. i'm looking for software to improve audio.. i'm slowly transferring my cassettes and just want some ideas of software to try.. i've tried quite a few so far and nothing really more than increasing sound but need something a little more advanced. i know it mainly depends on the sound card and i have a decent one but the tapes are old, some have never made it to cd and want to rescue them as much as possible. think i've tried every free app out there.. atm tho i'm using Diamond Cut Audio which i like the most at this point and still use but just wondering what else is out there.. Thanks.

 

Audacity is one i have used in the past that is free.