Stroller/Infant Car seat Rain Covers:
We purchased an infant car seat rain cover that worked on the car seat and our travel stroller. Since M is over a year the infant car seat has been retired but we still have the cover. Basically it is plastic cover with mesh sides for breathability when I googled around for bike seat covers it was the same thing! This is a great quick fix for rainy/cold days to cover a front mounted seat and can go over a windscreen if you have one. You can monitor the little one but keep the wind and rain off of them. The cover we have is by Maxi Cosi and they run about $30.
Now not everyone may have used wet bags or know what a wet bag is but they are pretty common in the cloth diapering world. The bags are reusable and washable, they hold all the dirties without leaking out poop/pee and keep the smell all zippered in. We own two wet bags, one we still use for diapers, but it is also great for putting items like the wet clothes M soaked at the fountain this pass weekend. Our other wet bag is smaller and is delaminated aka no longer holds water. This little pouch is my go to when I am riding around the neighborhood with M on my pink bike. No pockets or basket is no issue I just clip it onto the Yepp and store cash and iphone right in it. Wet bags range is price, but you can find them all over Etsy and cloth diapering companies websites.
Skip Hop Stroller Bag:
This was a random eBay purchase when M was a newborn, it held all kinds of go to items I needed in hands reach on the stroller. Perfect for the times I couldn't be bothered to dig through the diaper bag. Today we use this bag on our bikes for extra storage. Sometimes it holds a diaper and wipes, other times snacks and water bottles. There is even a pouch on the side for water bottles. I use the velcro straps and put it on my handle bars when my husband uses he uses it on the frame of the bike. We both agree that this is something we will keep use on the bike future. I paid around $10 but that was eBay you can check out Skip Hop for pricing.
Now our diaper bag is actually a backpack we purchased from our local bike shop. We had a couple of diaper bags, but I realized a backpack was easier for me when M was tiny. I often carried him in a baby carrier on the front and then the bag went on the back. Let's be honest I still do this when I ride public transportation with him. I originally had a small baby messenger style bag but wanted a backpack that was large enough to in the future hold enough stuff for two kids. I scoured baby stores and websites, but couldn't find something both pleasing to the eye and functional. I turned to some local bike shops and bam, a local company, ReLoad had a bag that fit my needs. But I highly recommend any backpack for biking and babies. They are classic and comfy! For me I am glad this bag will be a lifetime of use beyond babies.
P.S. In no way was I compensated for loving on these products
P.P.S. I have a list of some other baby stuff that we use for biking, I hope to expand this post in the future