Endowment.top - I do not feel this domain
TravelInsurance.one, LifeInsurance.one - keywords here are very strong. It would require deep analysis whether there exists some end user for connection of .ONE with these keywords. It does not go very well together, but I can imagine there might be insurance provider using ONE or 1 as its brand or part of the brand..in this case they might be interested.
For example, I googled up
http://www.onepath.com.au/, which is insurance provider and it provides also life insurance. These types of companies might consider some type of rebrand..but, you need to really think how to propose it to them, and mainly what type of benefit they can have from it
As per appraisal value, if you can persuade big insurance company so they actually want the name, sky is the limit. It all goes down to perceived value they can get from the name. Estibot appraisal has no value in this case, only your creativity and ability to find user who can benefit from the name. At the moment, many end users are not actively searching for new gTLDs in most cases, so domainers need to actively contact end users.