In my opinion, the best Bitcoin wallet for Android is the Bitcoin Wallet (also known as Schildbach wallet).
The only thing one needs to be aware of is the fact this wallet does not reveal the seed to you directly but rather encrypts it and allows you to save it locally as a file (can be also be saved in other places after encryption).
I haven't used it. So, the wallet forces you to make a digital backup of your seed even if it's in an encrypted format? Can you decrypt the seed manually (without using the native software) to check the seed words and make an offline backup or is there no such option? I don't like being forced to make digital backups if I don't want to.
Also, allows you to choose the fee you want to pay, but you can't accurately type how many sat/vB you want to pay, the minimum is about 2 Sat/vB last time I checked.
How do you enter the fees then if it can't be entered accurately? Maybe it only works with round numbers and not with decimals. Ledger Live has such a weird fee entry system.
so could you list here some opensource wallets for crypto holdings sir?? specially for altcoin holdings and for mobile usage. thank you very much.
People already mentioned some. You can try Unstoppable Wallet or AtomicDEX. The second one is also a decentralized exchange that bridges different cryptocurrencies.
For online wallet, if considering using it for small amount of money, you can use Electrum. Alternatively, you can use Bluewallet.
OP asked for clients with multi-coin support. Blue Wallet and Electrum are bitcoin-only wallets.