I don't know about websites with things to buy checklist. I have my own list that I created based on what I think I will need. It's quite long and hope it helps you
PixiePosh things to buy list
For us
Antenatal classes
Maternity photoshoot
Newborn photoshoot
Post natal jamu massage
Confinement package
4D scan
For me
Our mattress disposable protector in case of water bag burst
Nipple cream
Stretch mark cream
Maternity clothes (pants/dress/tops/front opening pajamas)
Belly wrap
Nursing bra
Nursing bra pads
Sanitary pads
Panties
Baby sleeping stuff
Cot bed
Sleeping bag
Blankets
10 in 1 pillow
Infant pillow - for use when a few months old
Beansprout pillow
Baby shusher
Cot bed mobile
Waterproof cot bed mattress protector
Wall decal
Fitted bed sheet
Swaddling blanket
UV anti dust mite vacuum
Baby feeding stuff
Breasts pump
Infant milk powder - in case no milk supply
Feeding bottles
Bottle teats
Bottle washing brush
UV bottle sterilizer
High chair with tray for meals - for use when introducing solid foods
Bowl set - for use when introducing solid foods
Plate - for use when introducing solid foods
Spoon set - for use when introducing solid foods
Sippy cup set - for use when introducing liquids
Roll up bib - for use when introducing solid foods
Baby safety stuff
Safety socket pack
Safety corner blocks
Safety gate
Baby bath and grooming
Hooded towels
Bath towels
Face towels
Bath wash set
Comb n brush set
Ear buds
Cotton balls
Nail filer
Nasal cleaner
Finger toothbrush
Baby diaper stuff
Diaper changing table
Diaper table changing pad
Diaper rash cream
Baby non talc powder
Cloth diaper
Disposable insert for cloth diaper
Wet wipes
Disposable diapers - in case as back up
Baby play stuff
Gym mat
Baby bouncer
Play pen - for use when baby start crawling
Baby travel stuff
Car seat
Baby carrier
Stroller
Diaper bag
Baby clothes
Baby laundry detergent
Laundry drying rack
Baby clothes (vests/rompers full suit/short sleeve body suit/socks/booties/mittens/hats/beanies)
Baby toys
Cot bed side toy
Toys and books - for use during later months
Soother toy
Teething toy
Pacifier - as back up
Other stuff
Baby thermometer
Gold anklet