I do buy DVD's and sets. With two provisos.
One, I rarely buy them new. This is a time when many people are getting rid of their CD and DVD collections and I live in an area where there are a number of secondhand and 'goodwill' stores, so my main problem is self-control. Second proviso, is that I like to be informed and surprised. I love to find things I want to find or know about but wasn't expecting to find.
Sounds like you are really enjoying yourself, I envy you.
On your list:-
Some of these I never watched back in the day, because I was for long periods, in situations where I couldn't watch TV regularly, not for any other reason.
UFO - have watched a few episodes, looks like it was a good show back in the day.
The Flash - I only watch free to air or what I can buy on DVD and Flash - the current series is not on free-to-air here. I did watch some of the original series tho, and quite liked it. I presume you are referring to that.
Voyage to the Bottom of the sea - also a good show, but I've never watched much of it. I do like the comics tho.
Lost in Space - A Classic for many reasons. I can't watch many movies or TV shows more than once - some of Lost in Space many times.
The current series - I have watched. Season one is a Curate's egg [ Parts of it were very good indeed] It;s better than it could have been in these WOKE times, but I can understand fans of the original not liking it.
Lost in Space | Official Trailer | Netflix
https://www.youtube.com/watch?v=fzmM0AB60QQ They made it serious, but thanks to the wonderful
Jonathan Harris, who stole the show, rewrote the 'Dr Smith' part and made the show his own, it was a comedy. You came home after school to watch DR Smith get his.
Jonathan Harris Lost In Space Interviewhttps://www.youtube.com/watch?v=F16Df3A5uooJonathan Harris on Guy Williams on "Lost in Space"https://www.youtube.com/watch?v=i4pwWio5NGkI like watching actors spark off each other. Billy Mumy and Jonathan Harris were genius together, made it look straightforward and simple, but that's what made the show so popular.
Lost in Space Exclusive: Bill Mumy Visits The Jupiter 2 ? Robot SurpriseSorry for the asides, made me realize how good that show really was.
https://www.youtube.com/results?search_query=billy+mumy+2020 Batman - I was, by the time Batman screened here, a Marvel and Gold Key fan, and didn't have the frame of mind to fully appreciate it's camp approach, but I watched it. Appreciate it more now. I like finding Adam West in obscure episodes of other series. he was a seriously underappreciated actor.
Should have done the 'Stan Lee type cameos' in all the Batman movies.
There is a strong tradition of that in all the Superman TV shows and Movies.
The Man from Uncle - Watched that religiously back in the day, and have since kept an eye on the careers and subsequent work of David McCallum and Robert Vaughn - both of them have rarely been in anything second rate.
Star Girl - Jeff Johns is either terrible or brilliant, Star Girl was one of his 'brilliant' ideas so I will be looking out for this one.
Sherlock Holmes - I have the Basil Rathbone box set and a box set of the Ronald Howard series among otter things.