Below is a list of bridges you can use, to transfer your funds from chain to chain. DYOR - this is just a collection. I have not used every bridge out there.
List of aggregators in this topic
- Celer Bridge
- Synapse Protocol (Multi-chain)
- Multichain
- Hop (ETH, MATIC, Arbitrum, Optimism)
- xPollinate (BSC, MATIC, FTM, xDAI)
- Transit (Multi-chain)
- Wormhole (Portalbridge)
- LayerSwap
- ChainHop
- PolyNetwork
- EvoDefi
- Matic Bridge
- Orbitchain
- Ren Project
- Binance Bridge
- xDAI Bridge
- KCC Bridge (ETH <> KSC)
- Nerve Bridge (BSC <> ETH)
- RelayChain (BSC, AVAX, MATIC, ETH, HECO)
- AVAX - ETH Bridge
- Meson
If you are too lazy to figure out your route, this spreadsheet might help. I forgot who made it, he (or she) should probably add their Twitter @ in the sheets 
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BTC bridges
If you have just BTC in a wallet, and want to get in DeFi:
Check your DeFI wallet holdings + yield farms