  The analytical package written in FORM presented in this paper allows the
computation of the complete set of Feynman Rules producing the Rational terms
of kind R2 contributing to the virtual part of NLO amplitudes in the Standard
Model of the Electroweak interactions. Building block topologies filled by
means of generic scalars, vectors and fermions, allowing to build these Feynman
Rules in terms of specific elementary particles, are explicitly given in the
Rxi gauge class, together with the automatic dressing procedure to obtain the
Feynman Rules from them. The results in more specific gauges, like the 't Hooft
Feynman one, follow as particular cases, in both the HV and the FDH dimensional
regularization schemes. As a check on our formulas, the gauge independence of
the total Rational contribution (R1 + R2) to renormalized S-matrix elements is
verified by considering the specific example of the H --> gamma-gamma decay
process at 1-loop. This package can be of interest for people aiming at a
better understanding of the nature of the Rational terms. It is organized in a
modular way, allowing a further use of some its files even in different
contexts. Furthermore, it can be considered as a first seed in the effort
towards a complete automation of the process of the analytical calculation of
the R2 effective vertices, given the Lagrangian of a generic gauge theory of
particle interactions.
