Tracking down the High Banks weapon and gear crates, when you first visit the hilltop town in Once Human, is the trickiest part of its exploration, but you'll need to find them if you want to complete every objective in the Explore High Banks mission. The town itself isn't too big, but there are quite a few buildings to investigate, plus a lot of monsters roaming around who make your job harder.
While the Mystical Crate is easy to find—guarded by the elite enemy in the centre of town—the other two are a little way out, so it's understandable if you missed them. All that said, here's where to find the High Banks weapon crate and gear crate to complete those objectives and get some loot.
You can find the High Banks weapon crate at map coordinates 5435,-5871 in a building with a red roof in the south of the town. You'll need to head through the main square to get here, so watch out for all of the stardust-infected monsters, including the giant balloon-headed Ede guarding the Mystical Chest.
Take the road leading up the hill and head through the open gate, then enter the building and go upstairs to find the weapon crate immediately on the first floor landing.
This chest contains:
You can find the High Banks gear crate at map coordinates 5275,-5870 in a second red-roofed building just to the west of the weapon crate. Follow the road up the hill—being wary of the ghoul enemies—until you reach the house at the very top with the open gate. Go inside, climb the stairs to the first floor, then head outside onto the wooden balcony to spot the gear crate on your left.
For some reason the game calls it an armor crate in the Explore High Banks mission, but this is definitely the one you're looking for. It contains:
The Mystical Crate is located at 5444,-5800, but I doubt you'll need those co-ordinates since it's right in the centre of town, guarded by the big balloon-headed elite monster, so it's hard to miss. The chest itself is on the stage with the grand opening sign and contains 40 S870 - Sandstorm FRAG Shotgun blueprints. If you lead the big enemy away it's easy to grab while it's distracted, or you can simply defeat the monster. I suggest tackling it at range and taking cover in the glass-fronted building behind the stage, since it's too big to get inside.