Many Irwin Allen shows are now available for online viewing (some may be restricted to US audiences). Below are links for each of the science fiction shows as well as The Lost World at Amazon.com (#ad).
Irwin Allen productions available to buy or rent on Amazon Prime (#ad)
Irwin Allen Memorabilia at Amazon US (#ad)
Irwin Allen Memorabilia at Amazon UK (#ad)
TV Guide: What's showing in the US