First off all of you people that hate pokemon go and don't play it please don't comment how you hate the game. We get it you don't follow the trends and your very special and you deserve lots of attention :D just not here.

I play Pokemon go most by biking around my town, we have a pretty nice community so its pretty safe to go were ever I want within reason, we also have a pretty hot summer, so some of the stuff on this list will be geared toward that. Basically I am making a check list of supplies you may want/need while playing Pokemon go.

PS: When I do pokemon go I often will do it 3 hours a clip so that's why I have some stuff like food on the list.

A bike: I use my bike as transportation as I can get places fast but still hatch eggs. I recommend if you have a mountain/street bike to use that because sometimes going up hills with a backpack of stuff can get hard if you can't shift to a lower gear
Backpack: This will contain most of the goodies you will bring with you, try and get a modest backpack so if you live a rough area people won't try and steal it.
Phone: So you can play the game silly
At least 1 bottle of 16 oz all natural spring water: The most important thing you can do to have a good day is stay hydrated both so you can have lots of energy and be healthy along with cool off. I often bring 2 bottles
Battery pack w/charger cable: Pokemon go can be battery consuming, and if its not for you you will also be out awhile, so a good charge will always help.
Pocket knife/cutting tool: Just in case you get in a sticky situation or just need to cut something its always good to have a knife.
Protein bar and sandwich: I often like to bring food with me so that I don't need to return home if I'm hungry. Protein bar I often eat while biking, and I'll sit down in the shade and pull out the sandwich if I'm extra hungry.
Phone case: If your holding the phone in your hand while biking and you drop your phone it could cause damage, I swear bye my otter box.
Band aid: I can't count how much times I cut myself then start bleeding everywhere ruining my new shirt. It's always good to have basic first aid stuff

EXTRA

Poke-walker/fit-bit: Personally I would use the poke-walker as its more fitting, but apparently those along with soul silver are REALLY expensive and rare. But this is because it feel rewarding after a long day of biking to see you just walked 20000 steps.
Para-cord bracelet: I have one of these. If you don't know what it is, its a bracelet made of rope that is the same grade as rope used in a military parachute, the bracelet can be quickly undone into a very large and strong rope. This is more of an emergency get lost/hurt tool
Smart watch: This is so you can easily see if someone is texting you on your bike maybe worried if you have been gone a while. A good smart watch that I LOVE is the martian notifier it looks great and works great, and is only $30
GoPro/camera: I always have a high quality video/picture quality device on me just in case. I like my GoPro because say I'm biking and I see a cool lake I can put it in the lake and look around or I can be biking and capture some cool footage.
Sunglasses: It can be bright sometimes

Most of all

Your integrity

That has been the list, I bring all this stuff with me whenever I go out pokemon-ing for the day. Let me know if you bring anything not on this list, cause I would love to add it on. It's always the worst to have biked 10 minutes away from home just to realize you maybe are thirsty or found something to take a picture of but don't have the supplies necessary.