The main one, Mrrzy, was the pledge to leave the EU with an "oven ready" deal. In the first week that was put in doubt by making any extension to leaving illegal. This means that if no deal is reached in time we will leave without a deal. Of course we all hope that a good deal will be achieved and there is time yet but it does show that BoJo's statement that he had a deal already was a lie

That was not my understanding of the oven-ready deal. My understanding was that it was a deal acceptable to the EU, and for which Parliament would vote, thus enabling us to leave the EU (on 31 Jan). There will still be negotiations to see what future trading terms will be, but that will be after we are out with the oven-ready deal.
As such it is not a broken pledge, it is one that will be completed on time on 31 Jan 2020.