Hello! The Corona is a pretty well-known model of diatonic accordion built by Hohner. It's a three row twelve bass instrument and yours is probably tuned A/D/G or G/C/F. They're decently built - particularly the older ones - and yours looks like an older one. At some point in the 60s they changed the grille design, going from a flat, flush-fitted grille to one with a raised rim. Yours has the flush grille, so it's 1960s or earlier. It has two voices, tuned slightly apart to get the traditional accordion tremolo sound, and when in good shape it can sell for quite a decent price. They're pretty popular in south American and Tex-Mex music, at least on your side of the world. However, it's unlikely to be in decent shape because of its age, and it will probably need tuning, revalving and rewaxing.
The Club IIB Victoria is another melodeon, but with a slightly different system. Unless it's been 'declubbed' to convert it into the standard system, there is a button in the middle of the keyboard that play the same note both when pulling the bellows and when pushing them. All the others will play two different notes. I also believe the bass system will be different to a standard melodeon, but I'm not an expert on Club models so I'm not sure. Club accordions were popular in Germany and central Europe for a good chunk of the last century. I seem to find that they are usually tuned in Bb/Eb or C/F. The third row is known as a 'helper' row, and contains accidentals (notes not included in the other two rows) and reversals (notes that are included on the other two rows, but in a different bellows direction). The Club IIB Victoria is a pretty decent two-voice instrument, but I don't really know its value because the club system is a bit archaic at this point. Yours was built in the 1930s, so unless it's been restored then it will need quite a bit of work doing on it.
As for the piano accordion, Titanos were really pretty good instruments, at least from what I've heard. Yours is by no means a high-end model - it's a student's instrument with the full 41 keys and 120 buttons, but with only three treble couplers and two on the bass. It's interesting, because two voices and three treble couplers denotes a non professional piano accordion, like your Titano, but professional diatonic accordions, like your Corona and Victoria, will often have two voices and no couplers at all. How strange. Anyway, it's not a high end instrument, but that doesn't mean it's not high quality. As far as I know, all the Titano models were at least decent, and lots were actually quite good. I guess your student Titano would be worth more than a similar student Crucianelli or Soprani. Still, it'll be worth very little if it's deteriorated or damaged inside. The outside looks lovely but inside is where it counts with accordions, and like the other two it will have gotten slowly worse over the 50-60 years it's been around. Unlike the other two which are tuned MM (two middle sets of reeds) this one is tuned LM (one low set and one middle set). This means it has a different sound. it's more full, and has no tremolo. This makes it better for jazz, and any sort of music where the tremolo sound is a little undesirable.
Anyway, that's my 2ps worth. For more information about the melodeons I would advise asking the good folks over at
www.melodeon.net, and for the Titano I would advise asking anyone here with more experience in Titanos than me!