My daughter is 16 months old & she is obsessed with pillows. I am wondering if it is ok for me to put a pillow in her cot & if so, what pillow is recommended? She currently sleeps per SID guidelines with nothing excepr her ergopouch sleeping bag.

While your daughter is out of the age range for SIDS, Red Nose recommends not introducing a pillow till a child is in a bed.
Older babies in a cot can be at an increased risk of a sleeping accident by using pillows and bumpers as a step to climb up and fall out of the cot.
It is safer to wait until the child starts to sleep in a bed before introducing a pillow or other soft bedding.
https://rednose.org.au/article/at-what-age-can-i-introduce-cot-bumpers-and-pillows