First of all, talk to your players. Flawed (because you’re not really looking for cursed, which should be a burden to all characters, while flaws could affect the user only) items are a lot of fun, but in my experience that depend on individual preferences of the players. For example, consider these categories (they could overlap, so just talk to the players, what do they prefer):
1. Likes roleplaying his character.
Add fluffy flaws. Uncontrolled bursts of laughter, rude remarks in the middle of a conversation with a powerful wizard, occasional gluttony - for those who like a little bit of slapstick. Amnesia, disturbing memories, nightmares - for those who prefer darker themes. The effects should not be too exaggerated - not to exclude other characters, but to make it clear that using the item is not without consequences.
2. Likes book-keeping her character.
Add crunchy flaws. Make a sword that collects charges with each hit and allows to spend them for increased to-hit chance, better crit range or energy damage. But make sure the sword can never have 0 or more than X charges, so that the “sword economy” is always a challenge. Or pool some items together - make a sword, an armor and and a belt of mighty constitution share a bonus: you can split a +3 every day between the three items.
3. Likes rolling dice
Add random flaws. Some flaws from the list of drawbacks seem well designed for this purpose. Make a sword that requires additional d6 roll after each critical hit and you select an effect from a random table. Make sure these effects do not affect other players too much, but sacrificing some money, fatigue, temporary ability penalty should be ok.
4. All players like to work together
Make items dependent on each other, similar to teamwork feats. This wand will only work if the rogue is fighting with that dagger and the fighter is using this shield. But if the rogue switched to this bow, the cleric could use that rod.
But again, discuss with your players. They can even design the flaws themselves (with you guidance and/or approval). Of course they should really be flaws - a fluffy flaw affecting social situations will not work well in a dungeon crawl, where you mostly meet dumb monsters. Dependent items won’t work if you have an ever-changing group of players.
Also, these items could grow with the players (a good idea for a low-magic world), gaining new flaws and new advantages.