I've got it a few days ago. 2 liards 1759, copper, mintage - 283000 pcs. Ruler - Maria Theresia von Habsburg.
5 centimes 1908, copper-nickel, weight - 2,5 g., size - 18 mm., thickness - 1,5 mm, mintage - 1500000 pcs. Engraver: Alphonse Michaux. Ruler^ grand duke Wilhelm IV (1905-1912).
I saw such patterns: 50 centimes 1914, 1 & 2 francs 1914. They were rather expensive: about 115 $ each other.
Grand Duke Jean I (1964-2000). 20 francs 1980, aluminium-bronze, weight - 8,65 g., size - 25,65 mm, thickness - 2,33 mm, mintage - 3000000 pcs. Engravers: Julien & Nina Lefevre.
5 centimes 1901, copper-nickel, weight - 2 g., size - 17 mm., thickness - 1,15 mm, mintage - 2000000 pcs. Engraver: Alphonse Michaux. Ruler: grand duke Adolphe (1890-1905).
Grand duchess Charlotte (1919-1964). 5 centimes 1924, copper-nickel, weight - 2,5 g., size - 17,9 mm, thickness - 1,24 mm, mintage - 3000000 pcs. Engraver: Jean Mich. Single release.
Grand duchess Charlotte (1919-1964). 1 franc 1928, nickel, weight - 5 g., size - 23 mm, thickness - 2 mm, mintage - 2000000 pcs. Engraver: Armand Bonnetain. Such coins were released at 1924, 1928 & 1935. Demonetized at January 1 1953.
I only have two from Luxembourg, one (a 1962 5 Franc) has already been featured in this thread, so here's the other, a 2002 20 Euro Cent:
Grand duchess Charlotte (1919-1964). 25 centimes 1930, bronze, weight - 5,5 g., size - 25 vv, thickness - 1,65 vv, mintage - 1000000 pcs. Engraver: Alexandre Everaerts. Single reliase. Demonetized at April 1939.
Are you looking for the 1870 2 1/2 in particular? I have an 1854 and a 1908 2 1/2 so far. Anyway, of the 1870 series, here's a 5 centimes I just got. I guess the sword and caduceus are the marks of Utrecht mint and it's then-mint master, which Luxembourg inexplicably borrowed for this series, prompting a protest from the Netherlands.