Here's another one I've proposed here before:

Galactic Orbit Parallax

The idea is that now that we have the large Earth-based interferometry telescopes coming on-line soon that we should specifically photograph nearby galaxies and background distant galaxies now (espeically in the directions near Cassiopeia), and again every decade, to measure the parallax distance to the closer galaxies to a high degree of accuracy. This might even get distances to the nearer quasars.

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Forming opinions as we speak