1) A gift card for a home & garden store
If you rent or own, there are always things you need to buy to make your space work. This is a gift that will get used.
2) Plants, planters or a hanging basket
Easy to find and available all year, this is a great gift for condo dwellers and house owners alike. Go low maintenance if you can and nothing too large. I'm currently loving succulent gardens as they fit both criteria. Feeling a DIY? Try the succulent wreath featured in the photo with how-to by prettyprudent.com.
3) Wine, salt and bread basket
Wine so your home has joy and prosperity, salt so that life will always have flavour and bread so the house will know no hunger. It's practical and easy to assemble. Plus you can include the sweet feel-good symbolism in the card or with tags on each item.
4) Address Labels
Easy to make or to order online; designs range from something fun with caricatures to traditional typeset. Inexpensive and personal.
As for no-nos: art (unless they have specifically selected a piece), furniture or anything to do with redecorating the house (paint, curtains, throw pillows, carpets, etc). These are far too personal and decisions that should be left to those who live there.
Happy gift shopping!