Select Custom Networks
Rather than having to load hundreds of blockchains on Polkadot.
First Create an Account or Import and Restore an Account, then the Network Selection screen will pop up. Search or scroll down to select the network(s) that you need to use, then hit Confirm. You will see all your selected networks when pressing the drop-down menu on the top. Apart from the four relay chains (Polkadot, Kusama, Westend Testnet & Rococo Testnet), all other networks are arranged in alphabetical order.
On the top drop-down menu, select Custom Networks. Search or scroll down to enable your desired networks, then press Done.