There are several ways to find the Custom token address on xDai using BlockScout.
1) BlockScout Bridged Token List. If you successfully bridged a token with the OmniBridge, you can find it at https://blockscout.com/poa/xdai/bridged-tokens.
2) Via your address on BlockScout. Paste your address into the BlockScout Search bar at https://blockscout.com/poa/xdai and click the Tokens tab to see all the tokens associated with your address on xDai.
3) Search by the token name in BlockScout.
4) When bridging, you can click on the executed ALM Transaction to locate newly minted tokens.
Guide was taken from Tokenbridge. For more information regarding the bridge, please refer to docs.tokenbridge.net.