Are there any bundle websites(such as Humble Bundle or Indie Gala) that accept Paysafecard

No.

Paysafecard is expensive and hard to use & get started (they don't accept just anybody), while Paypal accepts anybody without questions & is cheaper.

So pretty much nobody bothers it.

You could buy bitcoins with it (should be doable somewhere), and use the bitcoins on humble/indie bundle, greenmangaming and other sites.

I guess it is by far not the cheapest way (fees and such), but if you just got a paysafe card it might at least be A way.

Only gaming websites I know that accept them are Steam and GreenManGaming (GMG charges you 12% more for using a PaySafeCard)

Not sure if you know but you can get a debit card with paysafecard. You charge 10 euros into your account and they send you a debit card you can charge the same way using pins. I guess since it's a card it will be usable on all the sites.