Tektites have very specific strewnfields associated with (but usually some distance from) the impacts in which they were formed. Ukraine is not within any of those known strewnfields, with a couple of exceptions. The Nördlinger Ries Crater in Southern Germany from which Moldavite tektites were ejected has a strewnfield that stretches eastwards into Austria and the Czech Republic but there have been a smaller number of finds as far as the western areas of Ukraine. However, Moldavites are obviously glassy with a green hue (sometimes so dark that they need a strong backlight to show it) and have a very characteristic surface appearance, like this (which can weather into a flower-like appearance):
[My collection]
Also, microtektite-like spherules of impact glass have been found in Ukraine, probably associated with the Boltysh Crater, but they’re tiny. Some sellers in the crystal world have been offering larger spherical items claimed to be tektites from the Ilniyets crater in Ukraine as shown below but these are non-glassy pieces of impactite rock which have been artificially converted into polished spheres.
[Picture from Lisa Satin on the ‘Satin Crystals’ website]
The Zhamanshin Crater in Kazakhstan has yielded all kinds of oddly-shaped items termed ‘Irghizites’, which are often quite small like these:
[My collection]
However, although Kazakhstan isn’t a million miles from Ukraine, the strewnfield is rather small and doesn’t extend that far. Many Irghizites are actually found within the crater itself or the immediate vicinity and classed as impactites rather than true tektites which have seen atmospheric flight.
Pseudo-tektites having a similar appearance to tektites have been found all over the place, in areas which have no associated impact site. This one from Columbia, for example:
[My collection]
For items withwithout (or sometimes with) the characteristic glassiness, surface appearance or aerodynamic shapes (as in the Indochinite below) there are many geological possibilities for other pseudotektites.
[My collection]
From the pictures you posted, apart from the first picture of a Darwinite from Tasmania and the last picture from the Russian Wikipedia, I only see two items with potential resemblance to typical tektite forms: the lower item in the 6th and 7th pictures; and the hemispherical item in the 8th and 9th pictures
The first resembles a Rizalite, like this:
[My collection]
However, these are found only in the vicinity of the Philippines and the strewnfield definitely doesn’t extend as far as Ukraine. If you have purchased this rather than found it in Ukraine, then it may well be a Rizalite.
The other has some resemblance to ‘button tektites’ from Australia, like this one:
[Picture from H. Raab, licensed under the Creative Commons Attribution-Share Alike 2.0 Austria license
https://creativecommons.org/licenses/by-sa/2.0/at/deed.en]
The Australasian tektite strewnfield is huge and stretches all the way from southern Australia to southern China, but doesn’t extend as far as Ukraine. Also, the ‘crazed’ surface appearance of your specimen (and some of the others you have shown) is not at all typical of tektites and I suspect that it’s some kind of spherical concretion that has broken in half and weathered.
