Kenny Everett was a DJ on Capital Radio London. Many years ago he compiled his first Bottom 30.
He later followed this with another bottom 30.
Some of those records are very hard to find since there were very few copies and no-one really wants them (except other people after the bottom 30).
My lifelong aim is to find them all, at the time of writing I still have one of the first bottom 30 to find.
My record collection started in 1974 so mainly includes records from the mid-70s until the late 80s. It also includes 7" singles dating from the early 50s through to current CDs.
I have every UK chart single from the 80s, so most of my favourites are from these times.
To state the obvious my favourite group is ABBA, but you may find other interesting records in my favourites. There is also an alphabetical list of my Top 250.
There had been earlier picture discs, but the genre took off in the late 70s with "My Best Friend's Girl" by "The Cars".
In the late 70s and early 80s the Top 75 singles were based soley on record sales from a sample of shops. Sales could be affected by releasing special versions of singles or selling them cheap. One method was to include goodies such as free singles, free badges, etc. Another method was to release a limited-edition picture disc. Typically these were not easy to find and sometimes limited to "chart shops"
Typically there were 7"-singles, shaped picture discs and round 12" picture Discs. Some of these are worth money, others almost worthless!
Recently there have been several ABBA limited edition picture discs and box sets as part of celebrating 40 years since their albums came out.