Is there an altcoin that can still be mined with a home pc and give something back?
I would like to try mining just to see the process so that I can understand it better.
With the cpu : xmr (use claymore miner or xmr-stack)
With gpu (not too old : less than 4 years) it will depends on you gpu.
A good start for gpu mining is nvidia pascal or maxwell ( GTX 10xx or GTX 9xx, pascal is better in general), or amd RX480 or fury. Old amd cards like R9 390 or 290 and even 280X or hd7970 are good too but more heavy on the power usage. Gpu mining concern usually XMR, ETH, ZEC (claymore miner for amd, others for nvidia).
To begin you main mine at nicehash pool (you may even use nicehash miner) to gain directly btc.