I started a campaign a few months ago in a pretty similar situation. I've homebrewed a couple items so far (mainly weapons) but the DMG has had a couple great items I've modified or copied wholesale.
Magic Item Tables A and B in the DMG are populated with some really good low level utility items, so that'd be a good place to start and get some inspiration. A Bag of Holding or Rope of Climbing is always welcome in an adventuring party. Potions are great to provide specific utility (eg waterbreathing, invisibility, Spider Climb, etc) without giving them unfettered access to those powers - a rogue with a Ring of Invisibility is a lot more powerful in the long run than a rogue with a Potion of Invisibility.
Also consider what kind of gameplay you're going to be focusing on - if your adventures are heavy on exploring and navigation, an item that can detect true north will be invaluable, but the same item would be at best a curiosity in a hack'n'slash dungeon-crasher or political intrigue.
As for offensive gear, spell scrolls are always welcome (also on the tables) but you don't start seeing magic weapons and armor until you get on to the more powerful tables. That being said, I have come up with a few so far but a few of them might be a bit too powerful for a novice DM to hand out.
One of the more balanced ones is a shortsword that deals +1 lightning damage and when attuned has a pool of 3 charges that recharge daily; using a charge on a successful hit forces the target to take a DC 13 Constitution save or be stunned for 1 minute, and the target is allowed to retry the save at the end of each turn. If all the charges are depleted, there is a 20% chance each time the wielder scores a successful hit that the +1 lightning damage bonus is lost until the weapon recharges. (In my game, this weapon's bonus damage rises to +1d4 when attuned but that's because of the otherwise low damage output of the player who owns it).
Feel free to use this, but remember - powerful items at low levels should have proportionate downsides. A plain +1 weapon doesn't call for much tweaking, but a greataxe that deals +2d4 bonus fire damage should probably force the wielder to act in strange ways, like eating parts of their victims on pain of breaking attunement or something.