Yes, some archive converters can handle TAR.GZ and 7Z formats together. One option is Softaken Archive Converter Software.It supports many formats - ZIP, RAR, 7Z, TAR, TAR.GZ, TAR.BZ2, etc. You can also batch convert several files in a combination of formats at a time with no file corruption. The process is simple and offline so you keep your files secure. A free demo version is available so you can try it out prior to purchase.