That 1973 Semi-Postal Steiner Page 90 is interesting as both values were also issued as black-prints with the denominations crossed out. Some of the Polish black-prints are a bit pricey but these two are quite affordable. On my personal stamp pages I've incorporated these sheets with others from the set so I've modified yours, Rod, & digitally added the blackprints.
The unknowns are rocket & balloon post commemorative labels.
The upper left label, blue with the numeral 6 & a rocket, was issued for the 6th experimental rocket flight conducted by the Krakow Aeroclub 3 Feb 1965. A total of 30,000 were printed in sheets of 20. My only listing is from the 1990 Polish specialized catalogue where they are priced for about $1.
The 4 balloon post labels are from the 33rd Poznan International Fair. They were issued 20 June 1964 & the labels bear the name of the 4 balloons, Poznan, Syrena, Katowice & Polonez. 16,000 of each were printed in sheets of 20, & again they are priced at $1.
There was tons of this type of material issued in Poland in the 1960s & even today, covers bearing these labels are listed on eBay
for a couple of bucks, but they don't sell there's just so much of it around & so few collectors of this material.
Tying in with the Copernicus sheet, here's a balloon cover dated 2 Sept 1973 from Poznan, the site of the world stamp exhibition "Poznan; '73"
Here's a sheetlet of the labels