The classic, B-Side game Behind Closed Doors is always one people recommend… https://spectrumcomputing.co.uk/entry/5998/ZX-Spectrum/Behind_Closed_Doors
(In the BCD series, the fun was to be had just as much from the responses to certain inputs as it was to solving the game.)
John’s Retarded Creatures and Caverns was highly rated back in the day… https://spectrumcomputing.co.uk/entry/6883/ZX-Spectrum/Retarded_Creatures_and_Caverns
From Out of A Dark Night Sky… https://spectrumcomputing.co.uk/entry/6337/ZX-Spectrum/From_Out_of_a_Dark_Night_Sky …shows his more serious side.
A word of warning about John’s games… Like many others of that era, they can sometimes rely on specific, well-know tropes and inputs of the time… For example, John quite liked using WORN as an extra command to INVENTORY. You might also have to LOOK BEHIND, LOOK UNDER, LOOK AROUND, LOOK (direction)… such as LOOK UP, LOOK LEFT… etc.