This is used with Night March/ Vengeance decks, i.e. decks that depend on having a large amount of Pokemon in the discard pile to do damage. Gaining popularity as the Ancient Origins Vespiquen is also capable of utilising this strategy, with Bee Revenge. It also has no retreat, all attacks require colourless energy, and can evolve on the first turn when paired with Forest of Giant Plants.
Head Ringer/ Jamming net
Since you don't understand how these cards work, the basic is that you cannot use either of these cards on your own Pokemon, you can only use them on your opponent's Pokemon.
E.g. you have Jamming Net. You can only use it on one of your opponent's EX Pokemon. You pick that Pokemon, attach it to them and the Pokemon will do 20 less damage.
This is very useful on Pokemon like Keldeo-Ex, which utlises Rush In to allow your opponent to switch Pokemon freely.
These 2 team flare cards are frequently seen paired with Seismitoad-EX, as Quaking Punch causes your opponent to be unable to use all item cards, meaning they can't use Tool Retriever, Scoop Up Cyclone or Super Scoop Up to get rid of the Head Ringer/ Jamming Net. Their only option is then to use a supporter card, Xerosic.
These two also see usage with sets that depend on tools, with Sigilyph piling tools via its Tool Box ability, and Trubbish dealing damage with Tool Drop. The Team Flare Head Ringer/ Jamming Net allow you to attach more tools, increasing the damage from Tool Drop (which is calculated from both your and your opponent's tools).