1. What do the following words have in common?

BAR
BAT
CAN
HER
RAD
RAY
YUK
WAG

2. What do the following words have in common?

PAN
SON
TON
OPT
TOP
STAT
IRON

Answers:

1. Each word can be changed  into a new one by adding the letters ON:

BARON, BATON, CANON, HERON, RADON, RAYON, YUKON, WAGON

2. Each word can be changed into a new one by adding the letters IC:

PANIC, SONIC, TONIC, OPTIC, TOPIC, STATIC, IRONIC

Note (#2): Other examples posted 12/15/18.