I'm doing some research for fiction writing, and I would like to have my plot points comply with known science whenever possible.

Regarding orbital transfers, I know that the fastest way from orbit A to orbit B (provided unlimited delta-V) is [practically a straight line](https://space.stackexchange.com/a/34932/32834), and that the transfer using the least amount of energy is a [Hohmann transfer](https://en.wikipedia.org/wiki/Hohmann_transfer_orbit).

I'm wondering about possible in-between transfers, provided a high amount (but finite) of delta-V is available. Could a "half Hohmann" transfer exist, traversing just 90º around the primary? A quarter Hohmann, etc.? Do they have a name? The story I'm writing would ideally have a continuum of orbit transfers, trading speed for energy expenditure.

Is there any open-source or freely online tool to calculate and simulate such transfers?