I have got around 10's of webpart solutions that I need to add and then deploy to all web applications, I would prefer if someone can share easiest way of doing it.
The easiest way would be to bundle them all into a single solution as there is no reason for each web part to be in it's own solution, aside from development silos.
Beyond that, you are likely looking at writing a very large batch file / powershell script that retracts the features, retracts the solutions, deletes the solutions, then adds the solutions, redeploys them and then activates the features on their respective web applications. The specifics of this will vary with the farm and with each solution but you are basically looking at a lot of this:
stsadm -o deactivatefeature ... stsadm -o retractsolution ... stsadm -o deletesolution ... stsadm -o addsolution ... stsadm -o deploysolution ... stsadm -o activatefeature ...