For my DDad, who's just started a community garden and takes huge delight in the tiniest developments in his plants:
An avocado vase
For my DP, who's just started retraining in carpentry and woodwork and is utterly in love with it:
Some classic woodworking books like this one and this one
A nice moisturiser from Kiehl's (because he's always asking to use mine)
An insulated coffee cup for early mornings on the way to school
And a lightweight vintage leather toolbelt to keep his stuff safe on him (his school isn't in the nicest of areas and he's always got one eye on his tools in case something 'walks off on its own').
And for DSS15, who's got into sports in a big way recently,
A new set of boxing gloves
Some resistance bands and a chin-up bar to train at home
A snack box from Japan
A new cologne
Two tickets to the local aquarium, so he can take his girlfriend on a different kind of date
Then I'll top things off with some stockingfillers: bars of Tony's Chocolonely, socks, a new keychain for DP, a little set of hot sauces for DSS, etc etc.