The phrase "a host of existing" is correct and usable in written English.
It can be used to refer to a large number of existing items, ideas, or entities in a particular context.
Example: "The research revealed a host of existing solutions to the problem that had not been considered before."
Alternatives: "a multitude of existing" or "a variety of existing".
On the one hand, there is a host of existing campaigns whose voices need to be more widely heard.
At a bare minimum it could give the UK access to an internal market of four nearby economies, as well as a host of existing global trade deals.
A host of existing works employs a constant, bulk value for porosity, even when the porous sample is attached to a free fluid.
An army spokesman said: "77th Brigade is being created to draw together a host of existing and developing capabilities essential to meet the challenges of modern conflict and warfare.
The proposed transmission strategies are based on a host of existing coding techniques and capacity results.
It's not exactly cheap, but neither are the methods needed to make semiconductor films for a host of existing electronic devices.
The money, he said, would be invested in a host of enterprises, including existing businesses within his Virgin Group of 200 companies, that are seeking ways to save energy or produce fuels, including aviation fuel, not derived from coal and oil.
But a host of other technologies, from existing schemes like splitting water to create hydrogen, compressing air in underground caverns, flywheels and heated gravel pits, to longer term bets like supercapacitors and superconducting magnets, are also jostling for position.
There's already Meebo, eBuddy, KoolIM, and a host of other services integrating existing chat services.
They are aggregates made up of primary substances together with a host of substantial and accidental forms existing in them and through them.
Ove Gudmestad, professor of marine and Arctic technology at the University of Stavanger in Norway, also raises a host of potential difficulties, notably the suitability of existing oilfield equipment, oil and gas price uncertainty and troubled relations with local people in the Arctic.
