Would you agree that mother's love is the only form of unconditional love?

No.. There are mothers who don’t feel any maternal love for their children, there are mothers that should’ve never been mothers. I’d like to think all mothers love their kids, as it supposed to be. But sadly, there are mothers who are just monsters.

No. Some women don't have the capacity of emotional love towards their own children. Some children are raised by other family members or they are adopted by a loving family. Some don't get that from blood but from friends. Love comes from anyone, not just by blood.

Amongst child bearing women some can show that kind of love indeed.
Amongst non child bearing women some can even more.

No. Many mothers do not have a bond with their children. I've seen unconditional love in the oddest places. It isn't always from family.

No, father's love is also unconditional. And grandparents' love.

No. My son’s love for his son is as unconditional as it gets.

No...

Yes pretty much. Probably because women are biologically programmed to protect and care for their child at all cost, to keep our species going.
All other forms of love are always conditional, often confused with lust and mostly temporary.