FWIW, I've been trying out this one: http://www.cpmspectrepi.webspace.virgin ... erter.html
(also available thro' amazon) over the last few weeks. So far I've tested it with four different VGA-equipped monitors and a T.V. that has both HDMI and VGA inputs (that's not yet shown on the external webpage above as I've yet to update it). Whilst it can be externally powered (and is supplied with a USB power cable) you do need to have a USB PSU available (or, like I have, one with two outputs - one for the Pi, the other for the converter).
Still running Raspbian Jessie or Stretch on some older Pi's (an A, B1, 2xB2, B+, P2B, 3xP0, P0W, 2xP3A+, P3B+, P3B, B+, and a A+) but Buster on the P4B's. See: https://www.cpmspectrepi.uk/raspberry_pi/raspiidx.htm