Items in a chest can have any intensity up to 5 x 100%, with a chance for some items to have 6 properties (presumably up to 100%, but most 6-property items seem to still be at the 500% cap, but that may just be bad luck)
However, with imbuing & reforging, even the 6x properties aren't worth that much. BUT....
There's two regular loot item types to look for in the chest, worth keeping:
1. Elemental damage weapons. For Treasure Chest loot (and even for monsters), Elemental damage is still considered a "property", even if it isn't for runic crafting, imbuing, and reforging. So, while elemental damage weapons with other properties might be of limited value, it is still possible for "clean" elemental damage weapons (only elemental damage, at any value from 10% to 100% in one type or cumulative types - such as a 100% poison sword with no other properties) to be loot - and those CAN be reforged (then enhanced after reforging, to change any remaining physical damage to elemental).
2. Jewelry. Simply, Chests have the best possible intensities and quantities of jewelry outside of the revamped dungeons (and no cursed junk), and even if you don't find loot that is mind-blowing, you will find stuff for an imbuer to improve on, such as things that are max standard intensity in 1-2 properties (that require relics or hard to get ingredients), and either no properties or stuff complementary to the maxed-out stuff that you can imbue higher. Many people will still pay well for a good non-imbued item that can't be gotten otherwise, and don't want to farm for weeks or months trying to go through items in Shame looking for something for the ultra-rare non-cursed/non-bad-luck jewelry piece. And, until they add a tinker reforging tool, it will probably stay that way.
My mage uses a ring to complete her suit that started out with 3 of the 5 properties she needed at 100% and a small bit of luck, that came from a chest, that I added the 5th property to (15% physical to overcap so that I'm still 70 with protection cast), and filled up the remaining bit by increasing the Luck. You can save millions with your imbuer by utilizing T-chest rings and bracelets as starting points.