The bells parts, marked "tiefe glocken" (deep bells), are usually played on a rolling rack of tubular chimes. Sometimes the pitches are specified, as in M3, and sometimes they're not (M6 and M7). In the case of the Abbado M3, it looks to me that they're using "bell plates". These are metallic plates of different sizes, in order to get the different pitches. Sometimes actual bells will be used, but they're usually much smaller than huge church bells (an octave higher, in other words). Mahler had a set of his own bells casted for the "Resurrection" symphony. This has been well documented in a number of Mahler bio's. I wonder if he hauled them around for some of the other symphonies as well (?). They'll sometimes use long strips of metal as well. Sometimes they'll use longer chimes, in order to be in a lower octave, and will have the player climb a ladder in order to strike the tops of them. The main thing you need to know is this: sometimes the actually pitch is specified, and sometimes it's not (ad lib.).
Tam-tam is old European nomenclature for a large gong of unspecified pitch. Interestingly enough, the Chinese do not refer to those instruments as "tam-tams". They generally call them Chau Gongs, and the Chinese manufacture theirs in Wuhan. Mahler never specifies a pitch for his tam-tams (gongs). However, in the Resurrection symphony, there are separate parts for high and low tam-tams. You'll hear this at one spot in the first movement, as well as at the end of the symphony, where there are alternating salvos involving two tam-tams and three "tiefe glocken" of unspecified pitch. Actually tuned notes for gongs are an exception. You'll hear them very prominently in Messiaen's music, as well Puccini's "Turandot", and the Vaughan-Williams 8th symphony (finale).
Other common Mahler percussion instruments include cymbals - both plates (hand held) and suspended - bass drum, timpani (sometimes two sets, with two players), triangle, rute (thin birch branches played against the shell of the bass drum), Holzklapper (M5/III), snare drum (sometimes muted), and glockenspiel. They sometimes use a Xylophone in M10/IV, but that's not a Mahler thing (started with Cooke). The "Holzklapper" part is sometimes played on a woodblock, but that's technically not correct. A Holzklapper is sometimes called a wood-slap, or wood-clapper: two boards hinged together at one end. They're not easy to use at fast tempi, so the players often times prefer using a woodblock. I like the sound of a real Holzklapper in M5/III.
In M7, Mahler specifies a keyboard glockenspiel. They seldom use those, actually, but those parts really should be doubled when using regular glockenspiels. In M3/I and M7/V, there are spots where Mahler specifies that the bass drum and cymbals be played by one person. When that happens, they attach a cymbal to the top of the bass drum. The player plays the bass drum with one hand - usually the right hand (if they're right handed), and hold a cymbal with the other hand. He or she then strikes that cymbal against the one that's mounted to the bass drum. If you've seen a performance of Berg's "Lulu", the circus barker at the beginning of the opera does that repeatedly.
Mahler never used castanets, but they might fun to hear in M7 (just kidding!). M6, of course, has the famous hammer in the finale, which is to sound non-metallic. Lately, it's become fashionable to use big wooden boxes with a sound hole on the front face. Big wooden butcher tables can be satisfactory too. Of course, wooden surfaces should be struck with big wooden mallets that look something like a sledge hammer. With Mahler, the fun never ends.