Reddit mentions of Hanes Men's Long Sleeve Cool Dri T-Shirt UPF 50+, Medium, 2 Pack ,Safety Green

Winter Clothing/Underwear
In the fall I would wear whatever sweater was on sale at Goodwill.
For the colder winter months I wore a heavy Carhartt jacket and layered as necessary, normally using old/retired ARMY-issued polypropylene underwear.
I bought this around 7 years ago and it's awesome to have in cold weather.

Long Sleeve
For a long sleeve I would always wear these Hanes Cool Dri T-Shirt's in the summer. They claim 50+ UPF (Ultraviolet Protection Factor) though I'm sure that high of a rating only applies to the black ones and it will slowly go down as you put it through the wash. I bought the safety green ones over a year ago and haven't noticed any change in sun protection so far. They were holding up too witch was impressive with my line of work at the time (railroad labor).

Pants
I started wearing whatever blue jeans I found at Goodwill but they would always end up having holes after a month or so. I used that saved money and waited to for a 25% off sale to buy a few pairs of Duluth Firehouse pants (the originals, not those quick-dry things). I've returned 1 pair so far after 2 years even though I staggered them every day. I suspect I may have over-washed them (weekly)?

Hats
I was required to wear a hard hat so I bought this sun shade that wrapped around the brim, it worked out very nicely because 50% of the work involved bending over, exposing the back of your neck to the sun.

Socks
I bought Darn Tough socks and haven't looked back since.

Boots
I went through a few brands of boots before I found the perfect pair of Chippewa's. All other boots I tried were uncomfortable in the toe area. I was restricted to certain boot requirements from the railroad: 8", defined heel, safety toe, laced. I also put on some KG's Boot Guard before I wore out the leather on the toe area, use masking tape to make it look good! As for boot care, I opted for Obenauf's Heavy Duty LP because of the water and chemical resistance. Any time I needed to clean my boots I used Dawn (yes, the dish soap). For a thorough (bi-yearly) cleaning I used Murphy Oil Soap (yes, the wood cleaner).

Lunch Box
As for a lunch box, a basic small cooler/ice chest will do the job just fine for storing hot or cold items (not both at once!). They're well insulated, cheap, and beat broken zippers, ripped cloth, or dented metal any day.

Canteen
COLD: I bought this Coleman 1 Gallon Jug about 5 years ago at Goodwill for $2 and it still looks brand new today.
HOT: This Stanley One Hand Vacuum Mug was the best money I ever spent. It's awesome for driving without spillage and relatively easy to use while wearing insulated gloves. Sadly my first one was ran over by a coworker but I quickly bought another.

Sunscreen
Find whatever works for you, but keep in mind that high SPF ratings are pretty much marketing. SPF 15 = 94% UVB protection and SPF 45 = 98% UVB protection. As far as I'm aware you cannot obtain 100% UVB protection from sunscreen.

Sunglasses
Again, find whatever feels most comfortable to you, everybody is different. I was required to wear safety glasses which means polycarbonate lenses, they are known to scratch easily. Because of that, I found a pair that could be cheap enough to replace when necessary. Yes, my company did provide them, but they were incredibly uncomfortable to wear for 8+ hours a day.

Other
Having a few bandanas will always come in handy.
If you need gloves, your leather choices are between grain and patched. Grain is much more expensive, takes some breaking into, is water resistant and very durable. Patched is pretty much the exact opposite of grain. My goto brand was Kinco.

I may add more if I can think of anything else.

EDIT 1 - Forgot a link..