We already know that we have to download Bitcoin Core wallet if we want to contribute the network by running the full node of the blockchain.
But it will be a tedious job download the full chain of size 80 GB again if there happens something wrong with one's wallet and it needs to restart a wallet from the beginning.
So is there a recent bootstrap file available anywhere so that I can keep it as a backup in case I need it whenever I start a new wallet?
Or can anyone help me out on how to create a bootstrap file myself directly from the wallet files?
Technical helps are much appreciated

Do not use online wallet? If you dont wanna run fullnode/node on bitcoin network?
Use offline wallet example
http://www.coinmotion.com/