Lamotrigine stabilises neuronal membranes by use-dependent blockade of voltage-gated $Na^+$ channels, damping repetitive firing and presynaptic glutamate release. This pharmacology makes it strong against partial (focal) seizures and secondarily generalised / primary generalised tonic-clonic seizures.
Cross-checking the options: myoclonic jerks may be provoked by lamotrigine, absence seizures respond better to ethosuximide and valproate, and atonic drops belong to Lennox-Gastaut management where lamotrigine is adjunctive only. The cleanest, board-favoured indication among the four is generalised tonic-clonic seizures.
\[\boxed{\text{Lamotrigine is particularly useful for GTCS}}\]