Size charts:

Size charts will vary depending on the brand. Some are charts in inches, and some are based on US clothing sizes. Unfortunately it will be inconsistent since I'm using the information given on the manufacturer's websites and they provide different information. Choose what you think is the best for you and decide if you like fitted tops or a size up for a looser fit. I am listing exactly which brands and style numbers I am using, so you know exactly what you are getting. You can perhaps compare them to shirts you already own or check online to see how they fit on others.
I am including thumbnails of the shirts that look like the mockups so you can easily pinpoint which shirt is which.

Men's T-Shirts

Anvil 980

	S	M	L	XL	2XL	3XL
Length (inches)	27	28	29	30	31	32
Width (inches)	18	20	22	24	26	28

 

Next Level 3600

	XS	S	M	L	XL	2XL	3XL
Body Length	27	28	29	30	31	32	33
Body Length Tolerance	1/2	1/2	1/2	1/2	1/2	1/2	1/2
Body Width	17 1/2	19	20 1/2	22	24	26	28
Body Width Tolerance	1/2	1/2	1/2	1/2	1/2	1/2	1/2

 

Women's T-Shirts

Anvil 880

Sizes	Width (IN)	Length (IN)
S	17.25	25.5
M	19.25	26
L	21.25	27
XL	23.25	28
2XL	25.25	28.5

 

Next Level 3300

	S	M	L	XL	2XL
Body Length	25 3/8	26	26 5/8	27 1/4	27 7/8
Body Length Tolerance	1/2	1/2	1/2	1/2	1/2
Body Width	15 1/4	16 1/4	17 1/4	18 3/4	20 1/4
Body Width Tolerance	1/2	1/2	1/2	1/2	1/2

 

Bella / Canvas (6004) 
(Gamer orange druid tee)

	S	M	L	XL	2XL
Body Length	26 1/4	26 3/4	27 3/8	28	28 5/8
Body Length Tolerance	3/8	3/8	3/8	3/8	3/8
Body Width	16	16 3/4	17 3/4	18 3/4	19 3/4
Body Width Tolerance	1/2	1/2	1/2	1/2	1/2
Sleeve Length	6 1/4	6 1/2	6 3/4	7 1/4	7 1/2

 

Bella Canvas 8413L Triblend T-Shirt
(includes the hardcore gamer collection Electric Guitar, lipsticks, and Ruin My Makeup designs)

This shirt is form fitting and may be tight. Size up for a more comfortable fit!

	S	M	L	XL	2XL
Length	26	26 ½	27 ⅛	27 ¾	28 ⅜
Width	15 ¾	16 ½	17 ½	18 ½	19 ½

 

Women's Tank Tops

Spandex Jersey Tank and Racerback tank 
Next Level 3533 and 6633

	XS	S	M	L	XL	2XL
HPS length	25 3/4	26 3/8	27	27 5/8	28 1/4	28 7/8
Bust 1" below armhole	13	14	15	16	17 1/2	19

 

Triblend Racerback Tank
Next Level 6733

	XS	S	M	L	XL	2XL
Body Length	25 7/8	26 1/2	27 1/8	27 3/4	28 3/8	29
Body Length Tolerance	1/2	1/2	1/2	1/2	1/2	1/2
Body Width	15	16	17	18	19 1/2	21
Body Width Tolerance	1/2	1/2	1/2	1/2	1/2	1/2

 

Women's Muscle Tank
Bella Canvas 8805

(This shirt has low arm holes, which means the sides of your bra may show)

Small- 2-4
Medium 6-10
Large 10-14

Cap Sleeve Muscle Tank
Alternative 4013

XS	S	M	L	XL	2X	3X
BUST	30-31"	32-33"	34-35"	36-37"	38-39"	40-41"
WAIST	23-25"	25-27"	27-29"	29-31"	31-33"	33-35"
HIP	34-36"	36-38"	38-40"	40-41"	42-43"	43-44"

 

Women's Flowy V-Neck
Bella Canvas 8805

Small- 2-4
Medium 6-10
Large 10-14

Terry Racerback Tank
Next Level 6933 (loose fit)

	S	M	L	XL
Body Length	27 3/8	28	28 5/8	29 1/4
Body Length Tolerance	1/2	1/2	1/2	1/2
Body Width	15 1/2	16 1/2	17 1/2	19
Body Width Tolerance	1/2	1/2	1/2	1/2

 

Ringer Tank 
Bella Canvas 1534

XS	25.75"	31"
S	26.38"	33"
M	27"	35"
L	28.63"	37"
XL	28.25"	39"

 

Women's Sweatshirts

Bella Canvas 7501
(The neck hole is large enough to wear off the shoulder)

Small Sizes 2-4
Medium Sizes 6-8
Large Sizes 8-10
Extra Large 10-14 

Cadet Jacket
Bella Canvas 807

	S	M	L	XL
Body Length Front	23 3/4	24 1/4	24 3/4	25 1/4
Body Width	16 1/2	17 1/4	18 1/4	19 1/4